T-SQL 1=1 Performance Hit

Question

For my SQL queries, I usually do the following for SELECT statements:

SELECT ...
FROM table t
WHERE 1=1
  AND t.[column1] = @param1
  AND t.[column2] = @para         


        

Answer 1

No, SQL Server is smart enough to omit this condition from the execution plan since it's always TRUE.

Same is true for Oracle, MySQL and PostgreSQL.

Answer 2

No performance hit. Even if your WHERE clause is loaded with a large number of comparisons, this is tiny.

Best case scenario is that it's a bit-for-bit comparison. Worse case is that the digits are evaluated as integers.