Question

我有以下选择声明。

WITH cte AS
(
   SELECT MAX(logDate) AS Daily
   FROM PhysicalDriveSize
   GROUP BY DATEADD(m, DATEDIFF(m, 0, logDate), 0)
)
SELECT CAST(MIN(t.logDate) AS DATE) AS [Date], Drive, MIN(t.Free) AS [PercentagFree]
FROM PhysicalDriveSize AS t
JOIN cte AS m
ON t.logDate = m.Daily
WHERE t.Free <= 10 AND t.Free >= 0 
GROUP BY Drive, logDate

我想根据前面的结果做一些行动。

WITH cte AS
(
   SELECT MAX(logDate) AS Daily
   FROM PhysicalDriveSize
   GROUP BY DATEADD(m, DATEDIFF(m, 0, logDate), 0)
)
SELECT MIN(t.Free) AS [PercentagFree]
FROM PhysicalDriveSize AS t
JOIN cte AS m
ON t.logDate = m.Daily
WHERE t.Free <= 10 AND t.Free >= 0 
GROUP BY Drive, logDate
IF t.Free <= 10 AND t.Free >= 5
PRINT 'Warning'
Else
PRINT 'Critical'

如果我执行if语句，我会收到以下错误：

Msg 4104, Level 16, State 1, Line 13 The multi-part identifier "t.Free" could not be bound. Msg 4104, Level 16, State 1, Line 13 The multi-part identifier "t.Free" could not be bound

如何在没有错误的情况下使用if语句？

Answer 1

尝试使用case when then，如下所示：

WITH cte AS
(
   SELECT MAX(logDate) AS Daily
   FROM PhysicalDriveSize
   GROUP BY DATEADD(m, DATEDIFF(m, 0, logDate), 0)
)
SELECT MIN(t.Free) AS [PercentagFree],
case when t.Free <= 10 AND t.Free >= 5 then 'Warning'
     else 'Critical' end
FROM PhysicalDriveSize AS t
JOIN cte AS m
ON t.logDate = m.Daily
WHERE t.Free <= 10 AND t.Free >= 0 
GROUP BY Drive, logDate

修改

如果要发送消息，可以尝试创建一个临时变量，如

DECLARE @x int; WITH cte AS ( SELECT MAX(logDate) AS Daily FROM PhysicalDriveSize GROUP BY DATEADD(m, DATEDIFF(m, 0, logDate), 0) ) SELECT @x = MIN(t.Free) AS [PercentagFree] FROM PhysicalDriveSize AS t JOIN cte AS m ON t.logDate = m.Daily WHERE t.Free <= 10 AND t.Free >= 0 GROUP BY Drive, logDate if(@x is not null) PRINT 'Warning' Else PRINT 'Critical'

Answer 2

你可以像这样使用：

IF(t.Free <= 10 AND t.Free >= 0, 'Warning', 'Critical') as free

如何在SQL Select语句中使用If else

2 个答案: