Question

我有这样的Case-When条款;

(CASE WHEN A.YAZ_ADRES IS NULL
         THEN (B.IS_ADRES1 +' '+B.IS_ADRES2) 
         ELSE A.YAZ_ADRES END)

我想在THEN

之后使用条件

例如;

(CASE WHEN A.YAZ_ADRES IS NULL
         THEN (IF B.TUZ = 'T' THEN (B.IS_ADRES1 +' '+B.IS_ADRES2) ELSE ((B.EV_ADRES1 +' '+B.EV_ADRES2)))
         ELSE A.YAZ_ADRES END)

如何在Case-When中使用嵌套条件？

Answer 1

嵌套另一个CASE而不是IF

Answer 2

您可以使用CASE WHEN ... THEN ... (WHEN ... THEN ...)+ ELSE ... END。它返回匹配THEN条件的第一个的WHEN表达式：

CASE WHEN A.YAZ_ADRES IS NULL AND B.TUZ = 'T'
       THEN B.IS_ADRES1 +' '+B.IS_ADRES2
     WHEN A.YAZ_ADRES IS NULL 
       THEN B.EV_ADRES1 +' '+B.EV_ADRES2
     ELSE A.YAZ_ADRES
END

Answer 3

(CASE WHEN A.YAZ_ADRES IS NULL          
  THEN (CASE WHEN B.TUZ = 'T' THEN (B.IS_ADRES1 +' '+B.IS_ADRES2) ELSE ((B.EV_ADRES1 +' '+B.EV_ADRES2)) END)          
ELSE A.YAZ_ADRES END)

Answer 4

您可以像这样嵌套CASE子句：

(CASE WHEN A.YAZ_ADRES IS NULL
  THEN
    (CASE WHEN B.TUZ = 'T'
      THEN (B.IS_ADRES1 +' '+B.IS_ADRES2)
      ELSE ((B.EV_ADRES1 +' '+B.EV_ADRES2))
    END)
  ELSE A.YAZ_ADRES
END)

SQL：子句时的嵌套条件

4 个答案: