Max or Default

Question

What is the best way to get the Max value from a LINQ query that may return no rows  If I just do  Dim x    From y In context MyTable            Where y MyField   value            Select y MyCounter  Max   I get an error when the query returns no rows  I could do  Dim x    From y In context MyTable            Where y MyField   value            Select y MyCounter            Order By MyCounter Descending  FirstOrDefault   but that feels a little obtuse for such a simple request  Am I missing a better way to do it   UPDATE  Here s the back story  I m trying to retrieve the next eligibility counter from a child table  legacy system  don t get me started      The first eligibility row for each patient is always 1  the second is 2  etc   obviously this is not the primary key of the child table   So  I m selecting the max existing counter value for a patient  and then adding 1 to it to create a new row  When there are no existing child values  I need the query to return 0  so adding 1 will give me a counter value of 1   Note that I don t want to rely on the raw count of child rows  in case the legacy app introduces gaps in the counter values  possible   My bad for trying to make the question too generic

User · Answer

You could always add Double MinValue to the sequence  This would ensure that there is at least one element and Max would return it only if it is actually the minimum  To determine which option is more efficient  Concat  FirstOrDefault or Take 1    you should perform adequate benchmarking   double x   context MyTable      Where y   gt  y MyField    value       Select y   gt  y MyCounter       Concat new double   Double MinValue        Max

User · Answer

Another possibility would be grouping  similar to how you might approach it in raw SQL   from y in context MyTable group y MyCounter by y MyField into GrpByMyField where GrpByMyField Key    value select GrpByMyField Max     The only thing is  testing again in LINQPad  switching to the VB LINQ flavor gives syntax errors on the grouping clause  I m sure the conceptual equivalent is easy enough to find  I just don t know how to reflect it in VB   The generated SQL would be something along the lines of   SELECT  t1   MaxValue  FROM       SELECT MAX  t0   MyCounter  AS  MaxValue    t0   MyField      FROM  MyTable  AS  t0      GROUP BY  t0   MyField        AS  t1  WHERE  t1   MyField     p0   The nested SELECT looks icky  like the query execution would retrieve all rows then select the matching one from the retrieved set    the question is whether or not SQL Server optimizes the query into something comparable to applying the where clause to the inner SELECT  I m looking into that now     I m not well-versed in interpreting execution plans in SQL Server  but it looks like when the WHERE clause is on the outer SELECT  the number of actual rows resulting in that step is all rows in the table  versus only the matching rows when the WHERE clause is on the inner SELECT  That said  it looks like only 1  cost is shifted to the following step when all rows are considered  and either way only one row ever comes back from the SQL Server so maybe it s not that big of a difference in the grand scheme of things

User · Answer

Think about what you re asking   The max of  1  2  3  -1  -2  -3  is obviously 3  The max of  2  is obviously 2  But what is the max of the empty set      Obviously that is a meaningless question  The max of the empty set is simply not defined  Attempting to get an answer is a mathematical error  The max of any set must itself be an element in that set  The empty set has no elements  so claiming that some particular number is the max of that set without being in that set is a mathematical contradiction   Just as it is correct behavior for the computer to throw an exception when the programmer asks it to divide by zero  so it is correct behavior for the computer to throw an exception when the programmer asks it to take the max of the empty set  Division by zero  taking the max of the empty set  wiggering the spacklerorke  and riding the flying unicorn to Neverland are all meaningless  impossible  undefined   Now  what is it that you actually want to do

User · Answer

Why Not something more direct like   Dim x   context MyTable Max Function DataItem  DataItem MyField   Value

User · Answer

Think about what you re asking   The max of  1  2  3  -1  -2  -3  is obviously 3  The max of  2  is obviously 2  But what is the max of the empty set      Obviously that is a meaningless question  The max of the empty set is simply not defined  Attempting to get an answer is a mathematical error  The max of any set must itself be an element in that set  The empty set has no elements  so claiming that some particular number is the max of that set without being in that set is a mathematical contradiction   Just as it is correct behavior for the computer to throw an exception when the programmer asks it to divide by zero  so it is correct behavior for the computer to throw an exception when the programmer asks it to take the max of the empty set  Division by zero  taking the max of the empty set  wiggering the spacklerorke  and riding the flying unicorn to Neverland are all meaningless  impossible  undefined   Now  what is it that you actually want to do

User · Answer

Since DefaultIfEmpty isn t implemented in LINQ to SQL  I did a search on the error it returned and found a fascinating article that deals with null sets in aggregate functions  To summarize what I found  you can get around this limitation by casting to a nullable within your select  My VB is a little rusty  but I think it d go something like this   Dim x    From y In context MyTable            Where y MyField   value            Select CType y MyCounter  Integer    Max   Or in C    var x    from y in context MyTable          where y MyField    value          select  int  y MyCounter  Max

User · Answer

I think the issue is what do you want to happen when the query has no results   If this is an exceptional case then I would wrap the query in a try catch block and handle the exception that the standard query generates   If it s ok to have the query return no results  then you need to figure out what you want the result to be in that case   It may be that  David s answer  or something similar will work    That is  if the MAX will always be positive  then it may be enough to insert a known  bad  value into the list that will only be selected if there are no results   Generally  I would expect a query that is retrieving a maximum to have some data to work on and I would go the try catch route as otherwise you are always forced to check if the value you obtained is correct or not   I d rather that the non-exceptional case was just able to use the obtained value   Try    Dim x    From y In context MyTable               Where y MyField   value               Select y MyCounter  Max        continue working with x     Catch ex As SqlException            do error processing     End Try

User · Answer

You could always add Double MinValue to the sequence  This would ensure that there is at least one element and Max would return it only if it is actually the minimum  To determine which option is more efficient  Concat  FirstOrDefault or Take 1    you should perform adequate benchmarking   double x   context MyTable      Where y   gt  y MyField    value       Select y   gt  y MyCounter       Concat new double   Double MinValue        Max

User · Answer

Think about what you re asking   The max of  1  2  3  -1  -2  -3  is obviously 3  The max of  2  is obviously 2  But what is the max of the empty set      Obviously that is a meaningless question  The max of the empty set is simply not defined  Attempting to get an answer is a mathematical error  The max of any set must itself be an element in that set  The empty set has no elements  so claiming that some particular number is the max of that set without being in that set is a mathematical contradiction   Just as it is correct behavior for the computer to throw an exception when the programmer asks it to divide by zero  so it is correct behavior for the computer to throw an exception when the programmer asks it to take the max of the empty set  Division by zero  taking the max of the empty set  wiggering the spacklerorke  and riding the flying unicorn to Neverland are all meaningless  impossible  undefined   Now  what is it that you actually want to do

User · Answer

Since DefaultIfEmpty isn t implemented in LINQ to SQL  I did a search on the error it returned and found a fascinating article that deals with null sets in aggregate functions  To summarize what I found  you can get around this limitation by casting to a nullable within your select  My VB is a little rusty  but I think it d go something like this   Dim x    From y In context MyTable            Where y MyField   value            Select CType y MyCounter  Integer    Max   Or in C    var x    from y in context MyTable          where y MyField    value          select  int  y MyCounter  Max

User · Answer

I just had a similar problem  but I was using LINQ extension methods on a list rather than query syntax   The casting to a Nullable trick works there as well   int max   list Max i   gt   int  i MyCounter     0

User · Answer

Sounds like a case for DefaultIfEmpty  untested code follows    Dim x    From y In context MyTable            Where y MyField   value            Select y MyCounter  DefaultIfEmpty Max

User · Answer

One interesting difference that seems worth noting is that while FirstOrDefault and Take 1  generate the same SQL  according to LINQPad  anyway   FirstOrDefault returns a value--the default--when there are no matching rows and Take 1  returns no results    at least in LINQPad

User · Answer

You could always add Double MinValue to the sequence  This would ensure that there is at least one element and Max would return it only if it is actually the minimum  To determine which option is more efficient  Concat  FirstOrDefault or Take 1    you should perform adequate benchmarking   double x   context MyTable      Where y   gt  y MyField    value       Select y   gt  y MyCounter       Concat new double   Double MinValue        Max

User · Answer

You could always add Double MinValue to the sequence  This would ensure that there is at least one element and Max would return it only if it is actually the minimum  To determine which option is more efficient  Concat  FirstOrDefault or Take 1    you should perform adequate benchmarking   double x   context MyTable      Where y   gt  y MyField    value       Select y   gt  y MyCounter       Concat new double   Double MinValue        Max

User · Answer

Sounds like a case for DefaultIfEmpty  untested code follows    Dim x    From y In context MyTable            Where y MyField   value            Select y MyCounter  DefaultIfEmpty Max

User · Answer

Just to let everyone out there know that is using Linq to Entities the methods above will not work      If you try to do something like  var max   new   0         Concat  From y In context MyTable                  Where y MyField   value                  Select y MyCounter          Max      It will throw an exception      System NotSupportedException  The LINQ expression node type  NewArrayInit  is not supported in LINQ to Entities     I would suggest just doing    From y In context MyTable                      Where y MyField   value                      Select y MyCounter              OrderByDescending x  gt x  FirstOrDefault       And the FirstOrDefault will return 0 if your list is empty

User · Answer

Since  Net 3 5 you can use DefaultIfEmpty   passing the default value as an argument  Something like one of the followings ways   int max    from e in context Table where e Year    year select e RecordNumber  DefaultIfEmpty 0  Max    DateTime maxDate    from e in context Table where e Year    year select e StartDate    DateTime MinValue  DefaultIfEmpty DateTime MinValue  Max      The first one is allowed when you query a NOT NULL column and the second one is the way a used it to query a NULLABLE column  If you use DefaultIfEmpty   without arguments the default value will be that defined to the type of your output  as you can see in the Default Values Table    The resulting SELECT will not be so elegant but it s acceptable   Hope it helps

User · Answer

decimal Max    decimal   context MyTable Select e   gt  e MyCounter  Max       0

User · Answer

One interesting difference that seems worth noting is that while FirstOrDefault and Take 1  generate the same SQL  according to LINQPad  anyway   FirstOrDefault returns a value--the default--when there are no matching rows and Take 1  returns no results    at least in LINQPad

User · Answer

I just had a similar problem  my unit tests passed using Max   but failed when run against a live database     My solution was to separate the query from the logic being performed  not join them in one query  I needed a solution to work in unit tests using Linq-objects  in Linq-objects Max   works with nulls  and Linq-sql when executing in a live environment      I mock the Select   in my tests   var requiredDataQuery    dataRepo Select x   gt  new   x NullableDate1   NullableDate2      var requiredData ToList    var maxDate1   dates Max x   gt  x NullableDate1   var maxDate2   dates Max x   gt  x NullableDate2     Less efficient  Probably     Do I care  as long as my app doesn t fall over next time  Nope

User · Answer

Another possibility would be grouping  similar to how you might approach it in raw SQL   from y in context MyTable group y MyCounter by y MyField into GrpByMyField where GrpByMyField Key    value select GrpByMyField Max     The only thing is  testing again in LINQPad  switching to the VB LINQ flavor gives syntax errors on the grouping clause  I m sure the conceptual equivalent is easy enough to find  I just don t know how to reflect it in VB   The generated SQL would be something along the lines of   SELECT  t1   MaxValue  FROM       SELECT MAX  t0   MyCounter  AS  MaxValue    t0   MyField      FROM  MyTable  AS  t0      GROUP BY  t0   MyField        AS  t1  WHERE  t1   MyField     p0   The nested SELECT looks icky  like the query execution would retrieve all rows then select the matching one from the retrieved set    the question is whether or not SQL Server optimizes the query into something comparable to applying the where clause to the inner SELECT  I m looking into that now     I m not well-versed in interpreting execution plans in SQL Server  but it looks like when the WHERE clause is on the outer SELECT  the number of actual rows resulting in that step is all rows in the table  versus only the matching rows when the WHERE clause is on the inner SELECT  That said  it looks like only 1  cost is shifted to the following step when all rows are considered  and either way only one row ever comes back from the SQL Server so maybe it s not that big of a difference in the grand scheme of things

User · Answer

int max   list Any     list Max i   gt  i MyCounter    0    If the list has any elements  ie  not empty   it will take the max of the MyCounter field  else will return 0

User · Answer

I just had a similar problem  my unit tests passed using Max   but failed when run against a live database     My solution was to separate the query from the logic being performed  not join them in one query  I needed a solution to work in unit tests using Linq-objects  in Linq-objects Max   works with nulls  and Linq-sql when executing in a live environment      I mock the Select   in my tests   var requiredDataQuery    dataRepo Select x   gt  new   x NullableDate1   NullableDate2      var requiredData ToList    var maxDate1   dates Max x   gt  x NullableDate1   var maxDate2   dates Max x   gt  x NullableDate2     Less efficient  Probably     Do I care  as long as my app doesn t fall over next time  Nope

User · Answer

Think about what you re asking   The max of  1  2  3  -1  -2  -3  is obviously 3  The max of  2  is obviously 2  But what is the max of the empty set      Obviously that is a meaningless question  The max of the empty set is simply not defined  Attempting to get an answer is a mathematical error  The max of any set must itself be an element in that set  The empty set has no elements  so claiming that some particular number is the max of that set without being in that set is a mathematical contradiction   Just as it is correct behavior for the computer to throw an exception when the programmer asks it to divide by zero  so it is correct behavior for the computer to throw an exception when the programmer asks it to take the max of the empty set  Division by zero  taking the max of the empty set  wiggering the spacklerorke  and riding the flying unicorn to Neverland are all meaningless  impossible  undefined   Now  what is it that you actually want to do

User · Answer

One interesting difference that seems worth noting is that while FirstOrDefault and Take 1  generate the same SQL  according to LINQPad  anyway   FirstOrDefault returns a value--the default--when there are no matching rows and Take 1  returns no results    at least in LINQPad

User · Answer

litt late  but I had the same concern     Rephrasing your code from the original post  you want the max of the set S defined by   From y In context MyTable    Where y MyField   value    Select y MyCounter    Taking in account your last comment     Suffice to say that I know I want 0   when there are no records to select   from  which definitely has an impact   on the eventual solution   I can rephrase your problem as  You want the max of  0   S   And it looks like the proposed solution with concat is semantically the right one  -   var max   new   0             Concat  From y In context MyTable                      Where y MyField   value                      Select y MyCounter              Max

User · Answer

Sounds like a case for DefaultIfEmpty  untested code follows    Dim x    From y In context MyTable            Where y MyField   value            Select y MyCounter  DefaultIfEmpty Max

User · Answer

int max   list Any     list Max i   gt  i MyCounter    0    If the list has any elements  ie  not empty   it will take the max of the MyCounter field  else will return 0

User · Answer

Since  Net 3 5 you can use DefaultIfEmpty   passing the default value as an argument  Something like one of the followings ways   int max    from e in context Table where e Year    year select e RecordNumber  DefaultIfEmpty 0  Max    DateTime maxDate    from e in context Table where e Year    year select e StartDate    DateTime MinValue  DefaultIfEmpty DateTime MinValue  Max      The first one is allowed when you query a NOT NULL column and the second one is the way a used it to query a NULLABLE column  If you use DefaultIfEmpty   without arguments the default value will be that defined to the type of your output  as you can see in the Default Values Table    The resulting SELECT will not be so elegant but it s acceptable   Hope it helps

User · Answer

I think the issue is what do you want to happen when the query has no results   If this is an exceptional case then I would wrap the query in a try catch block and handle the exception that the standard query generates   If it s ok to have the query return no results  then you need to figure out what you want the result to be in that case   It may be that  David s answer  or something similar will work    That is  if the MAX will always be positive  then it may be enough to insert a known  bad  value into the list that will only be selected if there are no results   Generally  I would expect a query that is retrieving a maximum to have some data to work on and I would go the try catch route as otherwise you are always forced to check if the value you obtained is correct or not   I d rather that the non-exceptional case was just able to use the obtained value   Try    Dim x    From y In context MyTable               Where y MyField   value               Select y MyCounter  Max        continue working with x     Catch ex As SqlException            do error processing     End Try

User · Answer

Another possibility would be grouping  similar to how you might approach it in raw SQL   from y in context MyTable group y MyCounter by y MyField into GrpByMyField where GrpByMyField Key    value select GrpByMyField Max     The only thing is  testing again in LINQPad  switching to the VB LINQ flavor gives syntax errors on the grouping clause  I m sure the conceptual equivalent is easy enough to find  I just don t know how to reflect it in VB   The generated SQL would be something along the lines of   SELECT  t1   MaxValue  FROM       SELECT MAX  t0   MyCounter  AS  MaxValue    t0   MyField      FROM  MyTable  AS  t0      GROUP BY  t0   MyField        AS  t1  WHERE  t1   MyField     p0   The nested SELECT looks icky  like the query execution would retrieve all rows then select the matching one from the retrieved set    the question is whether or not SQL Server optimizes the query into something comparable to applying the where clause to the inner SELECT  I m looking into that now     I m not well-versed in interpreting execution plans in SQL Server  but it looks like when the WHERE clause is on the outer SELECT  the number of actual rows resulting in that step is all rows in the table  versus only the matching rows when the WHERE clause is on the inner SELECT  That said  it looks like only 1  cost is shifted to the following step when all rows are considered  and either way only one row ever comes back from the SQL Server so maybe it s not that big of a difference in the grand scheme of things

User · Answer

I ve knocked up a MaxOrDefault extension method  There s not much to it but its presence in Intellisense is a useful reminder that Max on an empty sequence will cause an exception  Additionally  the method allows the default to be specified if required       public static TResult MaxOrDefault lt TSource  TResult gt  this      IQueryable lt TSource gt  source  Expression lt Func lt TSource  TResult  gt  gt  selector      TResult defaultValue   default  TResult   where TResult   struct               return source Max selector     defaultValue

User · Answer

I ve knocked up a MaxOrDefault extension method  There s not much to it but its presence in Intellisense is a useful reminder that Max on an empty sequence will cause an exception  Additionally  the method allows the default to be specified if required       public static TResult MaxOrDefault lt TSource  TResult gt  this      IQueryable lt TSource gt  source  Expression lt Func lt TSource  TResult  gt  gt  selector      TResult defaultValue   default  TResult   where TResult   struct               return source Max selector     defaultValue

User · Answer

Since DefaultIfEmpty isn t implemented in LINQ to SQL  I did a search on the error it returned and found a fascinating article that deals with null sets in aggregate functions  To summarize what I found  you can get around this limitation by casting to a nullable within your select  My VB is a little rusty  but I think it d go something like this   Dim x    From y In context MyTable            Where y MyField   value            Select CType y MyCounter  Integer    Max   Or in C    var x    from y in context MyTable          where y MyField    value          select  int  y MyCounter  Max

User · Answer

I just had a similar problem  but I was using LINQ extension methods on a list rather than query syntax   The casting to a Nullable trick works there as well   int max   list Max i   gt   int  i MyCounter     0

User · Answer

decimal Max    decimal   context MyTable Select e   gt  e MyCounter  Max       0

User · Answer

Just to let everyone out there know that is using Linq to Entities the methods above will not work      If you try to do something like  var max   new   0         Concat  From y In context MyTable                  Where y MyField   value                  Select y MyCounter          Max      It will throw an exception      System NotSupportedException  The LINQ expression node type  NewArrayInit  is not supported in LINQ to Entities     I would suggest just doing    From y In context MyTable                      Where y MyField   value                      Select y MyCounter              OrderByDescending x  gt x  FirstOrDefault       And the FirstOrDefault will return 0 if your list is empty

User · Answer

For Entity Framework and Linq to SQL we can achieve this by defining an extension method which modifies an Expression passed to IQueryable lt T gt  Max      method   static class Extensions       public static TResult MaxOrDefault lt T  TResult gt  this IQueryable lt T gt  source                                                      Expression lt Func lt T  TResult gt  gt  selector          where TResult   struct               UnaryExpression castedBody   Expression Convert selector Body  typeof TResult             Expression lt Func lt T  TResult  gt  gt  lambda   Expression Lambda lt Func lt T TResult  gt  gt  castedBody  selector Parameters           return source Max lambda     default TResult             Usage    int maxId   dbContextInstance Employees MaxOrDefault employee   gt  employee Id      maxId is equal to 0 if there is no records in Employees table   The generated query is identical  it works just like a normal call to IQueryable lt T gt  Max      method  but if there is no records it returns a default value of type T instead of throwing an exeption

User · Answer

litt late  but I had the same concern     Rephrasing your code from the original post  you want the max of the set S defined by   From y In context MyTable    Where y MyField   value    Select y MyCounter    Taking in account your last comment     Suffice to say that I know I want 0   when there are no records to select   from  which definitely has an impact   on the eventual solution   I can rephrase your problem as  You want the max of  0   S   And it looks like the proposed solution with concat is semantically the right one  -   var max   new   0             Concat  From y In context MyTable                      Where y MyField   value                      Select y MyCounter              Max

User · Answer

Why Not something more direct like   Dim x   context MyTable Max Function DataItem  DataItem MyField   Value

User · Answer

For Entity Framework and Linq to SQL we can achieve this by defining an extension method which modifies an Expression passed to IQueryable lt T gt  Max      method   static class Extensions       public static TResult MaxOrDefault lt T  TResult gt  this IQueryable lt T gt  source                                                      Expression lt Func lt T  TResult gt  gt  selector          where TResult   struct               UnaryExpression castedBody   Expression Convert selector Body  typeof TResult             Expression lt Func lt T  TResult  gt  gt  lambda   Expression Lambda lt Func lt T TResult  gt  gt  castedBody  selector Parameters           return source Max lambda     default TResult             Usage    int maxId   dbContextInstance Employees MaxOrDefault employee   gt  employee Id      maxId is equal to 0 if there is no records in Employees table   The generated query is identical  it works just like a normal call to IQueryable lt T gt  Max      method  but if there is no records it returns a default value of type T instead of throwing an exeption

User · Answer

I think the issue is what do you want to happen when the query has no results   If this is an exceptional case then I would wrap the query in a try catch block and handle the exception that the standard query generates   If it s ok to have the query return no results  then you need to figure out what you want the result to be in that case   It may be that  David s answer  or something similar will work    That is  if the MAX will always be positive  then it may be enough to insert a known  bad  value into the list that will only be selected if there are no results   Generally  I would expect a query that is retrieving a maximum to have some data to work on and I would go the try catch route as otherwise you are always forced to check if the value you obtained is correct or not   I d rather that the non-exceptional case was just able to use the obtained value   Try    Dim x    From y In context MyTable               Where y MyField   value               Select y MyCounter  Max        continue working with x     Catch ex As SqlException            do error processing     End Try

User · Answer

I think the issue is what do you want to happen when the query has no results   If this is an exceptional case then I would wrap the query in a try catch block and handle the exception that the standard query generates   If it s ok to have the query return no results  then you need to figure out what you want the result to be in that case   It may be that  David s answer  or something similar will work    That is  if the MAX will always be positive  then it may be enough to insert a known  bad  value into the list that will only be selected if there are no results   Generally  I would expect a query that is retrieving a maximum to have some data to work on and I would go the try catch route as otherwise you are always forced to check if the value you obtained is correct or not   I d rather that the non-exceptional case was just able to use the obtained value   Try    Dim x    From y In context MyTable               Where y MyField   value               Select y MyCounter  Max        continue working with x     Catch ex As SqlException            do error processing     End Try

User · Answer

Sounds like a case for DefaultIfEmpty  untested code follows    Dim x    From y In context MyTable            Where y MyField   value            Select y MyCounter  DefaultIfEmpty Max

User · Answer

One interesting difference that seems worth noting is that while FirstOrDefault and Take 1  generate the same SQL  according to LINQPad  anyway   FirstOrDefault returns a value--the default--when there are no matching rows and Take 1  returns no results    at least in LINQPad

User · Answer

Another possibility would be grouping  similar to how you might approach it in raw SQL   from y in context MyTable group y MyCounter by y MyField into GrpByMyField where GrpByMyField Key    value select GrpByMyField Max     The only thing is  testing again in LINQPad  switching to the VB LINQ flavor gives syntax errors on the grouping clause  I m sure the conceptual equivalent is easy enough to find  I just don t know how to reflect it in VB   The generated SQL would be something along the lines of   SELECT  t1   MaxValue  FROM       SELECT MAX  t0   MyCounter  AS  MaxValue    t0   MyField      FROM  MyTable  AS  t0      GROUP BY  t0   MyField        AS  t1  WHERE  t1   MyField     p0   The nested SELECT looks icky  like the query execution would retrieve all rows then select the matching one from the retrieved set    the question is whether or not SQL Server optimizes the query into something comparable to applying the where clause to the inner SELECT  I m looking into that now     I m not well-versed in interpreting execution plans in SQL Server  but it looks like when the WHERE clause is on the outer SELECT  the number of actual rows resulting in that step is all rows in the table  versus only the matching rows when the WHERE clause is on the inner SELECT  That said  it looks like only 1  cost is shifted to the following step when all rows are considered  and either way only one row ever comes back from the SQL Server so maybe it s not that big of a difference in the grand scheme of things

User · Answer

Since DefaultIfEmpty isn t implemented in LINQ to SQL  I did a search on the error it returned and found a fascinating article that deals with null sets in aggregate functions  To summarize what I found  you can get around this limitation by casting to a nullable within your select  My VB is a little rusty  but I think it d go something like this   Dim x    From y In context MyTable            Where y MyField   value            Select CType y MyCounter  Integer    Max   Or in C    var x    from y in context MyTable          where y MyField    value          select  int  y MyCounter  Max

[c#] Max or Default?

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