SQL：大于或等于基于案例条件的where子句？

Question

I want to select such that if @reporteetype is 'immediate' then I would want to select rows where level is equal to 1, otherwise where level is greater than 2.

select a, b, c, level
from table1
where col1 ='x' and                              
      CASE @reporteetype WHEN 'immediate' THEN level = '2'   
                         WHEN 'other' THEN level > 2
                         else 1 = 1
      END 

This is a simplified version of my scenario. I do not want to use dynamic query. I want to know if this could be done using case?

Answer 1

You can do it using combinations of AND and OR conditions:

SELECT
    a, b, c, level
FROM table1
WHERE
    col1 = 'x'
    AND (
        (@reporteetype = 'immediate' AND level = 2)
        OR (@reporteetype = 'other' AND level > 2)
    )

Additional reading:

Catch-all Queries by Gail Shaw

Answer 2

Answer suggested by @Felix Pamittan is more efficient, however if you want to use CASE Expression, then it can be helpful:

SELECT  a
      , b
      , c
      , level
FROM    table1
WHERE   col1 = 'x'
        AND ( ( CASE WHEN @reporteetype = 'immediate' THEN '2'
                END ) = level
              OR ( CASE WHEN @reporteetype = 'other' THEN '2'
                   END ) > level
            )