Is there a way to make a TSQL variable constant?

Question

Is there a way to make a TSQL variable constant?

Answer 1

My workaround to missing constans is to give hints about the value to the optimizer.

DECLARE @Constant INT = 123;

SELECT * 
FROM [some_relation] 
WHERE [some_attribute] = @Constant
OPTION( OPTIMIZE FOR (@Constant = 123))

This tells the query compiler to treat the variable as if it was a constant when creating the execution plan. The down side is that you have to define the value twice.