How do I use T-SQL's Case/When?

Question

I have a huge query which uses case/when often. Now I have this SQL here, which does not work.

 (select case when xyz.something = 1
 then
     \'SOM         


        

Answer 1

As soon as a WHEN statement is true the break is implicit.

You will have to concider which WHEN Expression is the most likely to happen. If you put that WHEN at the end of a long list of WHEN statements, your sql is likely to be slower. So put it up front as the first.

More information here: break in case statement in T-SQL