Is a view faster than a simple query

Question

Is a   select    from myView   faster than the query itself to create the view  in order to have the same resultSet    select   from   query to create same resultSet as myView        It s not totally clear to me if the view uses some sort of caching making it faster compared to a simple query

User · Answer

In SQL Server at least  Query plans are stored in the plan cache for both views and ordinary SQL queries  based on query view parameters  For both  they are dropped from the cache when they have been unused for a long enough period and the space is needed for some other newly submitted query  After which  if the same query is issued  it is recompiled and the plan is put back into the cache   So no  there is no difference  given that you are reusing the same SQL query and the same view with the same frequency     Obviously  in general  a view  by it s very nature  That someone thought it was to be used often enough to make it into a view  is generally more likely to be  reused  than any arbitrary SQL statement

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My understanding is that a while back  a view would be faster because SQL Server could store an execution plan and then just use it instead of trying to figure one out on the fly  I think the performance gains nowadays is probably not as great as it once was  but I would have to guess there would be some marginal improvement to use the view

User · Answer

In SQL Server at least  Query plans are stored in the plan cache for both views and ordinary SQL queries  based on query view parameters  For both  they are dropped from the cache when they have been unused for a long enough period and the space is needed for some other newly submitted query  After which  if the same query is issued  it is recompiled and the plan is put back into the cache   So no  there is no difference  given that you are reusing the same SQL query and the same view with the same frequency     Obviously  in general  a view  by it s very nature  That someone thought it was to be used often enough to make it into a view  is generally more likely to be  reused  than any arbitrary SQL statement

User · Answer

Yes  views can have a clustered index assigned and  when they do  they ll store temporary results that can speed up resulting queries      Update  At least three people have voted me down on this one  With all due respect  I think that they are just wrong  Microsoft s own documentation makes it very clear that Views can improve performance   First  simple views are expanded in place and so do not directly contribute to performance improvements - that much is true   However  indexed views can dramatically improve performance     Let me go directly to the documentation       After a unique clustered index is created on the view  the view s result set is materialized immediately and persisted in physical storage in the database  saving the overhead of performing this costly operation at execution time    Second  these indexed views can work even when they are not directly referenced by another query as the optimizer will use them in place of a table reference when appropriate     Again  the documentation       The indexed view can be used in a query execution in two ways  The query can reference the indexed view directly  or  more importantly  the query optimizer can select the view if it determines that the view can be substituted for some or all of the query in the lowest-cost query plan  In the second case  the indexed view is used instead of the underlying tables and their ordinary indexes  The view does not need to be referenced in the query for the query optimizer to use it during query execution  This allows existing applications to benefit from the newly created indexed views without changing those applications    This documentation  as well as charts demonstrating performance improvements  can be found here   Update 2  the answer has been criticized on the basis that it is the  index  that provides the performance advantage  not the  View    However  this is easily refuted     Let us say that we are a software company in a small country  I ll use Lithuania as an example   We sell software worldwide and keep our records in a SQL Server database   We re very successful and so  in a few years  we have 1 000 000  records   However  we often need to report sales for tax purposes and we find that we ve only sold 100 copies of our software in our home country  By creating an indexed view of just the Lithuanian records  we get to keep the records we need in an indexed cache as described in the MS documentation   When we run our reports for Lithuanian sales in 2008  our query will search through an index with a depth of just 7  Log2 100  with some unused leaves    If we were to do the same without the VIEW and just relying on an index into the table  we d have to traverse an index tree with a search depth of 21     Clearly  the View itself would provide us with a performance advantage  3x  over the simple use of the index alone   I ve tried to use a real-world example but you ll note that a simple list of Lithuanian sales would give us an even greater advantage   Note that I m just using a straight b-tree for my example  While I m fairly certain that SQL Server uses some variant of a b-tree  I don t know the details   Nonetheless  the point holds   Update 3  The question has come up about whether an Indexed View just uses an index placed on the underlying table   That is  to paraphrase   an indexed view is just the equivalent of a standard index and it offers nothing new or unique to a view    If this was true  of course  then the above analysis would be incorrect   Let me provide a quote from the Microsoft documentation that demonstrate why I think this criticism is not valid or true      Using indexes to improve query performance is not a new concept  however  indexed views provide additional performance benefits that cannot be achieved using standard indexes    Together with the above quote regarding the persistence of data in physical storage and other information in the documentation about how indices are created on Views  I think it is safe to say that an Indexed View is not just a cached SQL Select that happens to use an index defined on the main table   Thus  I continue to stand by this answer

User · Answer

Yes  views can have a clustered index assigned and  when they do  they ll store temporary results that can speed up resulting queries      Update  At least three people have voted me down on this one  With all due respect  I think that they are just wrong  Microsoft s own documentation makes it very clear that Views can improve performance   First  simple views are expanded in place and so do not directly contribute to performance improvements - that much is true   However  indexed views can dramatically improve performance     Let me go directly to the documentation       After a unique clustered index is created on the view  the view s result set is materialized immediately and persisted in physical storage in the database  saving the overhead of performing this costly operation at execution time    Second  these indexed views can work even when they are not directly referenced by another query as the optimizer will use them in place of a table reference when appropriate     Again  the documentation       The indexed view can be used in a query execution in two ways  The query can reference the indexed view directly  or  more importantly  the query optimizer can select the view if it determines that the view can be substituted for some or all of the query in the lowest-cost query plan  In the second case  the indexed view is used instead of the underlying tables and their ordinary indexes  The view does not need to be referenced in the query for the query optimizer to use it during query execution  This allows existing applications to benefit from the newly created indexed views without changing those applications    This documentation  as well as charts demonstrating performance improvements  can be found here   Update 2  the answer has been criticized on the basis that it is the  index  that provides the performance advantage  not the  View    However  this is easily refuted     Let us say that we are a software company in a small country  I ll use Lithuania as an example   We sell software worldwide and keep our records in a SQL Server database   We re very successful and so  in a few years  we have 1 000 000  records   However  we often need to report sales for tax purposes and we find that we ve only sold 100 copies of our software in our home country  By creating an indexed view of just the Lithuanian records  we get to keep the records we need in an indexed cache as described in the MS documentation   When we run our reports for Lithuanian sales in 2008  our query will search through an index with a depth of just 7  Log2 100  with some unused leaves    If we were to do the same without the VIEW and just relying on an index into the table  we d have to traverse an index tree with a search depth of 21     Clearly  the View itself would provide us with a performance advantage  3x  over the simple use of the index alone   I ve tried to use a real-world example but you ll note that a simple list of Lithuanian sales would give us an even greater advantage   Note that I m just using a straight b-tree for my example  While I m fairly certain that SQL Server uses some variant of a b-tree  I don t know the details   Nonetheless  the point holds   Update 3  The question has come up about whether an Indexed View just uses an index placed on the underlying table   That is  to paraphrase   an indexed view is just the equivalent of a standard index and it offers nothing new or unique to a view    If this was true  of course  then the above analysis would be incorrect   Let me provide a quote from the Microsoft documentation that demonstrate why I think this criticism is not valid or true      Using indexes to improve query performance is not a new concept  however  indexed views provide additional performance benefits that cannot be achieved using standard indexes    Together with the above quote regarding the persistence of data in physical storage and other information in the documentation about how indices are created on Views  I think it is safe to say that an Indexed View is not just a cached SQL Select that happens to use an index defined on the main table   Thus  I continue to stand by this answer

User · Answer

Yes  views can have a clustered index assigned and  when they do  they ll store temporary results that can speed up resulting queries      Update  At least three people have voted me down on this one  With all due respect  I think that they are just wrong  Microsoft s own documentation makes it very clear that Views can improve performance   First  simple views are expanded in place and so do not directly contribute to performance improvements - that much is true   However  indexed views can dramatically improve performance     Let me go directly to the documentation       After a unique clustered index is created on the view  the view s result set is materialized immediately and persisted in physical storage in the database  saving the overhead of performing this costly operation at execution time    Second  these indexed views can work even when they are not directly referenced by another query as the optimizer will use them in place of a table reference when appropriate     Again  the documentation       The indexed view can be used in a query execution in two ways  The query can reference the indexed view directly  or  more importantly  the query optimizer can select the view if it determines that the view can be substituted for some or all of the query in the lowest-cost query plan  In the second case  the indexed view is used instead of the underlying tables and their ordinary indexes  The view does not need to be referenced in the query for the query optimizer to use it during query execution  This allows existing applications to benefit from the newly created indexed views without changing those applications    This documentation  as well as charts demonstrating performance improvements  can be found here   Update 2  the answer has been criticized on the basis that it is the  index  that provides the performance advantage  not the  View    However  this is easily refuted     Let us say that we are a software company in a small country  I ll use Lithuania as an example   We sell software worldwide and keep our records in a SQL Server database   We re very successful and so  in a few years  we have 1 000 000  records   However  we often need to report sales for tax purposes and we find that we ve only sold 100 copies of our software in our home country  By creating an indexed view of just the Lithuanian records  we get to keep the records we need in an indexed cache as described in the MS documentation   When we run our reports for Lithuanian sales in 2008  our query will search through an index with a depth of just 7  Log2 100  with some unused leaves    If we were to do the same without the VIEW and just relying on an index into the table  we d have to traverse an index tree with a search depth of 21     Clearly  the View itself would provide us with a performance advantage  3x  over the simple use of the index alone   I ve tried to use a real-world example but you ll note that a simple list of Lithuanian sales would give us an even greater advantage   Note that I m just using a straight b-tree for my example  While I m fairly certain that SQL Server uses some variant of a b-tree  I don t know the details   Nonetheless  the point holds   Update 3  The question has come up about whether an Indexed View just uses an index placed on the underlying table   That is  to paraphrase   an indexed view is just the equivalent of a standard index and it offers nothing new or unique to a view    If this was true  of course  then the above analysis would be incorrect   Let me provide a quote from the Microsoft documentation that demonstrate why I think this criticism is not valid or true      Using indexes to improve query performance is not a new concept  however  indexed views provide additional performance benefits that cannot be achieved using standard indexes    Together with the above quote regarding the persistence of data in physical storage and other information in the documentation about how indices are created on Views  I think it is safe to say that an Indexed View is not just a cached SQL Select that happens to use an index defined on the main table   Thus  I continue to stand by this answer

User · Answer

Select from a View or from a table will not make too much sense   Of course if the View does not have unnecessary joins  fields  etc  You can check the execution plan of your queries  joins and indexes used to improve the View performance   You can even create index on views for faster search requirements  http   technet microsoft com en-us library cc917715 aspx  But if you are searching like         than the sql engine will not benefit from an index on text column  If you can force your users to make searches like        than that will be fast  referred to answer on asp forums   https   forums asp net t 1697933 aspx Which is faster when using SELECT query VIEW or Table

User · Answer

EDIT  I was wrong  and you should see Marks answer above   I cannot speak from experience with SQL nbsp Server  but for most databases the answer would be no  The only potential benefit that you get  performance wise  from using a view is that it could potentially create some access paths based on the query  But the main reason to use a view is to simplify a query or to standardize a way of accessing some data in a table   Generally speaking  you won t get a performance benefit  I may be wrong  though    I would come up with a moderately more complicated example and time it yourself to see

User · Answer

EDIT  I was wrong  and you should see Marks answer above   I cannot speak from experience with SQL nbsp Server  but for most databases the answer would be no  The only potential benefit that you get  performance wise  from using a view is that it could potentially create some access paths based on the query  But the main reason to use a view is to simplify a query or to standardize a way of accessing some data in a table   Generally speaking  you won t get a performance benefit  I may be wrong  though    I would come up with a moderately more complicated example and time it yourself to see

User · Answer

My understanding is that a while back  a view would be faster because SQL Server could store an execution plan and then just use it instead of trying to figure one out on the fly  I think the performance gains nowadays is probably not as great as it once was  but I would have to guess there would be some marginal improvement to use the view

User · Answer

There is no practical different and if you read BOL you will find that ever your plain old SQL SELECT   FROM X does take advantage of plan caching etc

User · Answer

There should be some trivial gain in having the execution plan stored  but it will be negligible

User · Answer

It all depends on the situation   MS SQL Indexed views are faster than a normal view or query but indexed views can not be used in a mirrored database invironment  MS SQL    A view in any kind of a loop will cause serious slowdown because the view is repopulated each time it is called in the loop   Same as a query   In this situation a temporary table using   or   to hold your data to loop through is faster than a view or a query   So it all depends on the situation

User · Answer

Generally speaking  no  Views are primarily used for convenience and security  and won t  by themselves  produce any speed benefit  That said  SQL Server 2000 and above do have a feature called Indexed Views that can greatly improve performance  with a few caveats   Not every view can be made into an indexed view  they have to follow a specific set of guidelines  which  among other restrictions  means you can t include common query elements like COUNT  MIN  MAX  or TOP  Indexed views use physical space in the database  just like indexes on a table   This article describes additional benefits and limitations of indexed views   You Can     The view definition can reference one or more tables in the same database  Once the unique clustered index is created  additional nonclustered indexes can be created against the view  You can update the data in the underlying tables     including inserts  updates  deletes  and even truncates   You Can   t     The view definition can   t reference other views  or tables in other databases  It can   t contain COUNT  MIN  MAX  TOP  outer joins  or a few other keywords or elements  You can   t modify the underlying tables and columns  The view is created with the WITH SCHEMABINDING option  You can   t always predict what the query optimizer will do  If you   re using Enterprise Edition  it will automatically consider the unique clustered index as an option for a query     but if it finds a    better    index  that will be used  You could force the optimizer to use the index through the WITH NOEXPAND hint     but be cautious when using any hint

User · Answer

It all depends on the situation   MS SQL Indexed views are faster than a normal view or query but indexed views can not be used in a mirrored database invironment  MS SQL    A view in any kind of a loop will cause serious slowdown because the view is repopulated each time it is called in the loop   Same as a query   In this situation a temporary table using   or   to hold your data to loop through is faster than a view or a query   So it all depends on the situation

User · Answer

There is no practical different and if you read BOL you will find that ever your plain old SQL SELECT   FROM X does take advantage of plan caching etc

User · Answer

The purpose of a view is to use the query over and over again   To that end  SQL Server  Oracle  etc  will typically provide a  cached  or  compiled  version of your view  thus improving its performance   In general  this should perform better than a  simple  query  though if the query is truly very simple  the benefits may be negligible   Now  if you re doing a complex query  create the view

User · Answer

In SQL Server at least  Query plans are stored in the plan cache for both views and ordinary SQL queries  based on query view parameters  For both  they are dropped from the cache when they have been unused for a long enough period and the space is needed for some other newly submitted query  After which  if the same query is issued  it is recompiled and the plan is put back into the cache   So no  there is no difference  given that you are reusing the same SQL query and the same view with the same frequency     Obviously  in general  a view  by it s very nature  That someone thought it was to be used often enough to make it into a view  is generally more likely to be  reused  than any arbitrary SQL statement

User · Answer

I ran across this thread and just wanted to share this post from Brent Ozar as something to consider when using availability groups   Brent Ozar bug report

User · Answer

Generally speaking  no  Views are primarily used for convenience and security  and won t  by themselves  produce any speed benefit  That said  SQL Server 2000 and above do have a feature called Indexed Views that can greatly improve performance  with a few caveats   Not every view can be made into an indexed view  they have to follow a specific set of guidelines  which  among other restrictions  means you can t include common query elements like COUNT  MIN  MAX  or TOP  Indexed views use physical space in the database  just like indexes on a table   This article describes additional benefits and limitations of indexed views   You Can     The view definition can reference one or more tables in the same database  Once the unique clustered index is created  additional nonclustered indexes can be created against the view  You can update the data in the underlying tables     including inserts  updates  deletes  and even truncates   You Can   t     The view definition can   t reference other views  or tables in other databases  It can   t contain COUNT  MIN  MAX  TOP  outer joins  or a few other keywords or elements  You can   t modify the underlying tables and columns  The view is created with the WITH SCHEMABINDING option  You can   t always predict what the query optimizer will do  If you   re using Enterprise Edition  it will automatically consider the unique clustered index as an option for a query     but if it finds a    better    index  that will be used  You could force the optimizer to use the index through the WITH NOEXPAND hint     but be cautious when using any hint

User · Answer

Against all expectation  views are way slower in some circumstances    I discovered this recently when I had problems with data which was pulled from Oracle which needed to be massaged into another format  Maybe 20k source rows  A small table  To do this we imported the oracle data as unchanged as I could into a table and then used views to extract data   We had secondary views based on those views  Maybe 3-4 levels of views    One of the final queries  which extracted maybe 200 rows would take upwards of 45 minutes  That query was based on a cascade of views  Maybe 3-4 levels deep   I could take each of the views in question  insert its sql into one nested query  and execute it in a couple of seconds   We even found that we could even write each view into a temp table and query that in place of the view and it was still way faster than simply using nested views   What was even odder was that performance was fine until we hit some limit of source rows being pulled into the database  performs just dropped off a cliff over the space of a couple of days - a few more source rows was all it took   So  using queries which pull from views which pull from views is much slower than a nested query - which makes no sense for me

User · Answer

I would expect the two queries to perform identically   A view is nothing more than a stored query definition  there is no caching or storing of data for a view   The optimiser will effectively turn your first query into your second query when you run it

User · Answer

My understanding is that a while back  a view would be faster because SQL Server could store an execution plan and then just use it instead of trying to figure one out on the fly  I think the performance gains nowadays is probably not as great as it once was  but I would have to guess there would be some marginal improvement to use the view

User · Answer

It may be faster if you create a materialized view  with schema binding   Non-materialized views execute just like the regular query

User · Answer

The purpose of a view is to use the query over and over again   To that end  SQL Server  Oracle  etc  will typically provide a  cached  or  compiled  version of your view  thus improving its performance   In general  this should perform better than a  simple  query  though if the query is truly very simple  the benefits may be negligible   Now  if you re doing a complex query  create the view

User · Answer

There is no practical different and if you read BOL you will find that ever your plain old SQL SELECT   FROM X does take advantage of plan caching etc

User · Answer

Against all expectation  views are way slower in some circumstances    I discovered this recently when I had problems with data which was pulled from Oracle which needed to be massaged into another format  Maybe 20k source rows  A small table  To do this we imported the oracle data as unchanged as I could into a table and then used views to extract data   We had secondary views based on those views  Maybe 3-4 levels of views    One of the final queries  which extracted maybe 200 rows would take upwards of 45 minutes  That query was based on a cascade of views  Maybe 3-4 levels deep   I could take each of the views in question  insert its sql into one nested query  and execute it in a couple of seconds   We even found that we could even write each view into a temp table and query that in place of the view and it was still way faster than simply using nested views   What was even odder was that performance was fine until we hit some limit of source rows being pulled into the database  performs just dropped off a cliff over the space of a couple of days - a few more source rows was all it took   So  using queries which pull from views which pull from views is much slower than a nested query - which makes no sense for me

User · Answer

Yes  views can have a clustered index assigned and  when they do  they ll store temporary results that can speed up resulting queries      Update  At least three people have voted me down on this one  With all due respect  I think that they are just wrong  Microsoft s own documentation makes it very clear that Views can improve performance   First  simple views are expanded in place and so do not directly contribute to performance improvements - that much is true   However  indexed views can dramatically improve performance     Let me go directly to the documentation       After a unique clustered index is created on the view  the view s result set is materialized immediately and persisted in physical storage in the database  saving the overhead of performing this costly operation at execution time    Second  these indexed views can work even when they are not directly referenced by another query as the optimizer will use them in place of a table reference when appropriate     Again  the documentation       The indexed view can be used in a query execution in two ways  The query can reference the indexed view directly  or  more importantly  the query optimizer can select the view if it determines that the view can be substituted for some or all of the query in the lowest-cost query plan  In the second case  the indexed view is used instead of the underlying tables and their ordinary indexes  The view does not need to be referenced in the query for the query optimizer to use it during query execution  This allows existing applications to benefit from the newly created indexed views without changing those applications    This documentation  as well as charts demonstrating performance improvements  can be found here   Update 2  the answer has been criticized on the basis that it is the  index  that provides the performance advantage  not the  View    However  this is easily refuted     Let us say that we are a software company in a small country  I ll use Lithuania as an example   We sell software worldwide and keep our records in a SQL Server database   We re very successful and so  in a few years  we have 1 000 000  records   However  we often need to report sales for tax purposes and we find that we ve only sold 100 copies of our software in our home country  By creating an indexed view of just the Lithuanian records  we get to keep the records we need in an indexed cache as described in the MS documentation   When we run our reports for Lithuanian sales in 2008  our query will search through an index with a depth of just 7  Log2 100  with some unused leaves    If we were to do the same without the VIEW and just relying on an index into the table  we d have to traverse an index tree with a search depth of 21     Clearly  the View itself would provide us with a performance advantage  3x  over the simple use of the index alone   I ve tried to use a real-world example but you ll note that a simple list of Lithuanian sales would give us an even greater advantage   Note that I m just using a straight b-tree for my example  While I m fairly certain that SQL Server uses some variant of a b-tree  I don t know the details   Nonetheless  the point holds   Update 3  The question has come up about whether an Indexed View just uses an index placed on the underlying table   That is  to paraphrase   an indexed view is just the equivalent of a standard index and it offers nothing new or unique to a view    If this was true  of course  then the above analysis would be incorrect   Let me provide a quote from the Microsoft documentation that demonstrate why I think this criticism is not valid or true      Using indexes to improve query performance is not a new concept  however  indexed views provide additional performance benefits that cannot be achieved using standard indexes    Together with the above quote regarding the persistence of data in physical storage and other information in the documentation about how indices are created on Views  I think it is safe to say that an Indexed View is not just a cached SQL Select that happens to use an index defined on the main table   Thus  I continue to stand by this answer

User · Answer

It may be faster if you create a materialized view  with schema binding   Non-materialized views execute just like the regular query

User · Answer

It may be faster if you create a materialized view  with schema binding   Non-materialized views execute just like the regular query

User · Answer

Definitely a view is better than a nested query for SQL Server  Without knowing exactly why it is better  until I read Mark Brittingham s post   I had run some tests and experienced almost shocking performance improvements when using a view versus a nested query  After running each version of the query several hundred times in a row  the view version of the query completed in half the time  I d say that s proof enough for me

User · Answer

I ran across this thread and just wanted to share this post from Brent Ozar as something to consider when using availability groups   Brent Ozar bug report

User · Answer

In my finding  using the view is a little bit faster than a normal query  My stored procedure was taking around 25 minutes  working with a different larger record sets and multiple joins  and after using the view  non-clustered   the performance was just a little bit faster but not significant at all  I had to use some other query optimization techniques method to make it a dramatic change

User · Answer

In my finding  using the view is a little bit faster than a normal query  My stored procedure was taking around 25 minutes  working with a different larger record sets and multiple joins  and after using the view  non-clustered   the performance was just a little bit faster but not significant at all  I had to use some other query optimization techniques method to make it a dramatic change

User · Answer

Definitely a view is better than a nested query for SQL Server  Without knowing exactly why it is better  until I read Mark Brittingham s post   I had run some tests and experienced almost shocking performance improvements when using a view versus a nested query  After running each version of the query several hundred times in a row  the view version of the query completed in half the time  I d say that s proof enough for me

User · Answer

I would expect the two queries to perform identically   A view is nothing more than a stored query definition  there is no caching or storing of data for a view   The optimiser will effectively turn your first query into your second query when you run it

User · Answer

There should be some trivial gain in having the execution plan stored  but it will be negligible

User · Answer

There should be some trivial gain in having the execution plan stored  but it will be negligible

User · Answer

The purpose of a view is to use the query over and over again   To that end  SQL Server  Oracle  etc  will typically provide a  cached  or  compiled  version of your view  thus improving its performance   In general  this should perform better than a  simple  query  though if the query is truly very simple  the benefits may be negligible   Now  if you re doing a complex query  create the view

User · Answer

There should be some trivial gain in having the execution plan stored  but it will be negligible

User · Answer

EDIT  I was wrong  and you should see Marks answer above   I cannot speak from experience with SQL nbsp Server  but for most databases the answer would be no  The only potential benefit that you get  performance wise  from using a view is that it could potentially create some access paths based on the query  But the main reason to use a view is to simplify a query or to standardize a way of accessing some data in a table   Generally speaking  you won t get a performance benefit  I may be wrong  though    I would come up with a moderately more complicated example and time it yourself to see

User · Answer

Select from a View or from a table will not make too much sense   Of course if the View does not have unnecessary joins  fields  etc  You can check the execution plan of your queries  joins and indexes used to improve the View performance   You can even create index on views for faster search requirements  http   technet microsoft com en-us library cc917715 aspx  But if you are searching like         than the sql engine will not benefit from an index on text column  If you can force your users to make searches like        than that will be fast  referred to answer on asp forums   https   forums asp net t 1697933 aspx Which is faster when using SELECT query VIEW or Table

User · Answer

The purpose of a view is to use the query over and over again   To that end  SQL Server  Oracle  etc  will typically provide a  cached  or  compiled  version of your view  thus improving its performance   In general  this should perform better than a  simple  query  though if the query is truly very simple  the benefits may be negligible   Now  if you re doing a complex query  create the view

User · Answer

Definitely a view is better than a nested query for SQL Server  Without knowing exactly why it is better  until I read Mark Brittingham s post   I had run some tests and experienced almost shocking performance improvements when using a view versus a nested query  After running each version of the query several hundred times in a row  the view version of the query completed in half the time  I d say that s proof enough for me

User · Answer

There is no practical different and if you read BOL you will find that ever your plain old SQL SELECT   FROM X does take advantage of plan caching etc

User · Answer

In SQL Server at least  Query plans are stored in the plan cache for both views and ordinary SQL queries  based on query view parameters  For both  they are dropped from the cache when they have been unused for a long enough period and the space is needed for some other newly submitted query  After which  if the same query is issued  it is recompiled and the plan is put back into the cache   So no  there is no difference  given that you are reusing the same SQL query and the same view with the same frequency     Obviously  in general  a view  by it s very nature  That someone thought it was to be used often enough to make it into a view  is generally more likely to be  reused  than any arbitrary SQL statement

User · Answer

EDIT  I was wrong  and you should see Marks answer above   I cannot speak from experience with SQL nbsp Server  but for most databases the answer would be no  The only potential benefit that you get  performance wise  from using a view is that it could potentially create some access paths based on the query  But the main reason to use a view is to simplify a query or to standardize a way of accessing some data in a table   Generally speaking  you won t get a performance benefit  I may be wrong  though    I would come up with a moderately more complicated example and time it yourself to see

User · Answer

I would expect the two queries to perform identically   A view is nothing more than a stored query definition  there is no caching or storing of data for a view   The optimiser will effectively turn your first query into your second query when you run it

User · Answer

Definitely a view is better than a nested query for SQL Server  Without knowing exactly why it is better  until I read Mark Brittingham s post   I had run some tests and experienced almost shocking performance improvements when using a view versus a nested query  After running each version of the query several hundred times in a row  the view version of the query completed in half the time  I d say that s proof enough for me

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It may be faster if you create a materialized view  with schema binding   Non-materialized views execute just like the regular query

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Generally speaking  no  Views are primarily used for convenience and security  and won t  by themselves  produce any speed benefit  That said  SQL Server 2000 and above do have a feature called Indexed Views that can greatly improve performance  with a few caveats   Not every view can be made into an indexed view  they have to follow a specific set of guidelines  which  among other restrictions  means you can t include common query elements like COUNT  MIN  MAX  or TOP  Indexed views use physical space in the database  just like indexes on a table   This article describes additional benefits and limitations of indexed views   You Can     The view definition can reference one or more tables in the same database  Once the unique clustered index is created  additional nonclustered indexes can be created against the view  You can update the data in the underlying tables     including inserts  updates  deletes  and even truncates   You Can   t     The view definition can   t reference other views  or tables in other databases  It can   t contain COUNT  MIN  MAX  TOP  outer joins  or a few other keywords or elements  You can   t modify the underlying tables and columns  The view is created with the WITH SCHEMABINDING option  You can   t always predict what the query optimizer will do  If you   re using Enterprise Edition  it will automatically consider the unique clustered index as an option for a query     but if it finds a    better    index  that will be used  You could force the optimizer to use the index through the WITH NOEXPAND hint     but be cautious when using any hint

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I would expect the two queries to perform identically   A view is nothing more than a stored query definition  there is no caching or storing of data for a view   The optimiser will effectively turn your first query into your second query when you run it

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Generally speaking  no  Views are primarily used for convenience and security  and won t  by themselves  produce any speed benefit  That said  SQL Server 2000 and above do have a feature called Indexed Views that can greatly improve performance  with a few caveats   Not every view can be made into an indexed view  they have to follow a specific set of guidelines  which  among other restrictions  means you can t include common query elements like COUNT  MIN  MAX  or TOP  Indexed views use physical space in the database  just like indexes on a table   This article describes additional benefits and limitations of indexed views   You Can     The view definition can reference one or more tables in the same database  Once the unique clustered index is created  additional nonclustered indexes can be created against the view  You can update the data in the underlying tables     including inserts  updates  deletes  and even truncates   You Can   t     The view definition can   t reference other views  or tables in other databases  It can   t contain COUNT  MIN  MAX  TOP  outer joins  or a few other keywords or elements  You can   t modify the underlying tables and columns  The view is created with the WITH SCHEMABINDING option  You can   t always predict what the query optimizer will do  If you   re using Enterprise Edition  it will automatically consider the unique clustered index as an option for a query     but if it finds a    better    index  that will be used  You could force the optimizer to use the index through the WITH NOEXPAND hint     but be cautious when using any hint

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My understanding is that a while back  a view would be faster because SQL Server could store an execution plan and then just use it instead of trying to figure one out on the fly  I think the performance gains nowadays is probably not as great as it once was  but I would have to guess there would be some marginal improvement to use the view

[sql] Is a view faster than a simple query?

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