[sql] Equals(=) vs. LIKE

If you search for an exact match, you can use both, = and LIKE.

Using "=" is a tiny bit faster in this case (searching for an exact match) - you can check this yourself by having the same query twice in SQL Server Management Studio, once using "=", once using "LIKE", and then using the "Query" / "Include actual execution plan".

Execute the two queries and you should see your results twice, plus the two actual execution plans. In my case, they were split 50% vs. 50%, but the "=" execution plan has a smaller "estimated subtree cost" (displayed when you hover over the left-most "SELECT" box) - but again, it's really not a huge difference.

But when you start searching with wildcards in your LIKE expression, search performance will dimish. Search "LIKE Mill%" can still be quite fast - SQL Server can use an index on that column, if there is one. Searching "LIKE %expression%" is horribly slow, since the only way SQL Server can satisfy this search is by doing a full table scan. So be careful with your LIKE's !

Marc

Examples related to sql

Passing multiple values for same variable in stored procedure SQL permissions for roles Generic XSLT Search and Replace template Access And/Or exclusions Pyspark: Filter dataframe based on multiple conditions Subtracting 1 day from a timestamp date PYODBC--Data source name not found and no default driver specified select rows in sql with latest date for each ID repeated multiple times ALTER TABLE DROP COLUMN failed because one or more objects access this column Create Local SQL Server database

Examples related to performance

Why is 2 * (i * i) faster than 2 * i * i in Java? What is the difference between spark.sql.shuffle.partitions and spark.default.parallelism? How to check if a key exists in Json Object and get its value Why does C++ code for testing the Collatz conjecture run faster than hand-written assembly? Most efficient way to map function over numpy array The most efficient way to remove first N elements in a list? Fastest way to get the first n elements of a List into an Array Why is "1000000000000000 in range(1000000000000001)" so fast in Python 3? pandas loc vs. iloc vs. at vs. iat? Android Recyclerview vs ListView with Viewholder

Examples related to equals

this in equals method Why do we have to override the equals() method in Java? Compare two objects with .equals() and == operator Check if bash variable equals 0 Setting equal heights for div's with jQuery Java, how to compare Strings with String Arrays How can I express that two values are not equal to eachother? How to override equals method in Java How do you say not equal to in Ruby? Getting an element from a Set

Examples related to sql-like

SQL Server: use CASE with LIKE Create hive table using "as select" or "like" and also specify delimiter How do I find ' % ' with the LIKE operator in SQL Server? Using LIKE operator with stored procedure parameters SQL- Ignore case while searching for a string Is the LIKE operator case-sensitive with MSSQL Server? Using Eloquent ORM in Laravel to perform search of database using LIKE SQL 'LIKE' query using '%' where the search criteria contains '%' How to use "like" and "not like" in SQL MSAccess for the same field? MySQL SELECT LIKE or REGEXP to match multiple words in one record