Question

我现有的SQL语句

  UPDATE EMP 
  SET fte_adj = IIf((fte<1 Or fte Is Null) And [employment category] Like '*Full-Time*',1,
IIf((fte=0 Or fte Is Null) And [employment category] Like '*Part-Time*',0.25,fte));

它将更新表EMP

set fte_adj=1
if Full time (and fte<1 or null)

set fte_adj=0.25
if part time (and fte=0 or null)

otherwise fte_adj=fte

如何添加案例以检查另一个表SEC_EMP中是否存在employee_id的任何记录？

如果没有记录（0行），则set fte_adj=1

两个表都可以使用employee_id作为密钥

感谢

Answer 1

我用CASE改写了你的陈述（但我意识到IIF在2012年有效）：

UPDATE EMP 
SET fte_adj = 
  CASE WHEN (FTE < 1 OR FTE IS NULL) AND [employment category] Like '*Full-Time*'
    THEN 1
  ELSE
    CASE WHEN (FTE = 0 OR FTE IS NULL) AND [employment category] Like '*Part-Time*'
      THEN 0.25
    ELSE 
      CASE WHEN (SELECT COUNT(*) FROM SEC_EMP) = 0 
      THEN 1
      ELSE 
        FTE
      END
    END
  END

以下是一些示例Fiddle。

如果您更喜欢IIF逻辑，请转到：

UPDATE EMP 
SET fte_adj = 
  IIF ( (FTE < 1 OR FTE IS NULL) AND [employment category] Like '*Full-Time*' , 1 ,
      IIF ( (FTE = 0 OR FTE IS NULL) AND [employment category] Like '*Part-Time*' , 0.25, 
          IIF ( (SELECT COUNT(*) FROM SEC_EMP) = 0 , 1 , FTE ) 
          )
       )

更多Fiddle。

<强> - 编辑 -

如果我了解最新评论，您想更新仅存在于SEC_EMP表中的记录吗？如果是这样，只需加入表格：

UPDATE E 
SET fte_adj = 
  IIF ( (FTE < 1 OR FTE IS NULL) AND [employment category] Like '*Full-Time*' , 1 ,
      IIF ( (FTE = 0 OR FTE IS NULL) AND [employment category] Like '*Part-Time*' , 0.25, FTE 
          )
       )
FROM EMP E
  JOIN SEC_EMP SE ON E.employee_id = SE.employee_id

更多Fiddle。

Answer 2

试试这个：

UPDATE EMP 
SET fte_adj = CASE WHEN fte=1 Or fte Is Not Null And [employment category] Like '%Full-Time%'
THEN 1 ELSE .25 END AS 'Rate'

我还要添加

 WHERE [employment category] Like '%Full-Time%' OR [employment category] Like '%Part-Time%'

为了安全，取决于您的桌子。这适用于MS SQL btw，不知道'* syntax *'是什么。

Answer 3

您可以使用IIF语句添加EXISTS，只要它是相关的：

IIF(NOT EXISTS(
    SELECT [some column] FROM [some table]
    WHERE [some condition]
), 1, [some value OR another IIF statement])

Answer 4

sgeddes的case语句的更简单版本。

UPDATE EMP 
SET fte_adj = 
    CASE WHEN (FTE < 1 OR FTE IS NULL) AND [employment category] Like '*Full-Time*'
      THEN 1
    WHEN (FTE = 0 OR FTE IS NULL) AND [employment category] Like '*Part-Time*'
      THEN 0.25
    WHEN (SELECT COUNT(*) FROM SEC_EMP) = 0 
      THEN 1
    ELSE 
        FTE
    END

与IF不同的案例陈述可以有多个分支。它们也会短路，所以第一个被击中的分支就是它。例如，

CASE WHEN 1=1
WHEN 2=2
END

永远不会超过1 = 1分支。

在SQL更新语句中使用IIF

4 个答案: