当某些事情是真的时，有没有办法忽略CASE中的AND？

Question

我有这个Where条款

Select * From Student_Info si
Inner Join Certifications cc
Inner Join Cert_Earned ce

Where si.grad_date = @grad_date
AND cc.org_no = @org_no

但我需要一个额外的AND，如果结果是值为false，我应该忽略它，我会想要所有证书

AND cc.industrial = CASE WHEN @industrial = 0 THEN Do Nothing
                     Else @industrial

Answer 1

这通常表示为：

AND (@industrial = 0 OR ccc.industrial = @industrial)

Answer 2

听起来你只想添加一个在两个不同条件之间执行OR的谓词

AND (@industrial = 0 or ccc.industrial = @industrial)

Answer 3

您可以使用CASE函数执行类似的操作：

AND 1 = (CASE WHEN @industrial = 0 THEN 1 
              ELSE CASE WHEN cc.industrial = @industrial THEN 1 END
         END)

或者如果cc.industrial不可为空，那么可能：

AND cc.industrial = CASE WHEN @industrial = 0 THEN cc.industrial
                     Else @industrial END