SQL 更新查询中的 IF Else 语句

Question

I want to write if else in SQL Server Update Query.

Answer 1

UPDATE [dbo].[TempTable]
SET [Level1] = CASE WHEN A = -1 THEN 0 ELSE A END
   ,[Level2] = CASE WHEN A = -1 THEN 0 ELSE A END;

You need to use CASE in such scenarios. Try the above query..

Answer 2

If you insist on using IF , you can try the following:

IF

IF A = -1 BEGIN
    UPDATE [dbo].[TempTable]
    SET [Level1] = 0
       ,[Level2] = 0
END
ELSE BEGIN
    UPDATE [dbo].[TempTable]
    SET [Level1] = A
       ,[Level2] = A
END

IIF

UPDATE [dbo].[TempTable]
SET [Level1] = IIF(A = -1, 0, A)
   ,[Level2] = IIF(A = -1, 0, A)

Answer 3

You can use CASE statement, and If "A" is one of the column in your dbo.TempTable

DECLARE @Table TABLE(A INT,Level1 INT,Level2 INT)

INSERT @Table
SELECT -1, NULL, NULL UNION ALL
SELECT 1,NULL,NULL

UPDATE t SET 
    Level1 = CASE WHEN A = -1 THEN 0 ELSE A END,
    Level2 = CASE WHEN A = -1 THEN 0 ELSE A END
FROM @Table t

SELECT * FROM @Table

-- Result

A   Level1  Level2
-1  0   0
1   1   1

Answer 4

With case or IIF ;)

UPDATE [dbo].[TempTable]
SET [Level1] = IIF(A = -1 , 0 , A),  [Level2] = IIF(A = -1 , 0 , A)

Answer 5

This will work :

UPDATE [dbo].[TempTable]
SET [Level1] = IIF(A = -1, 0, A), [Level2] = IIF(A = -1, 0, A);