SQL SERVER UPDATE的赋值次序

SELECT 1, 10;

SELECT @i = 1, @j = 0

UPDATE @Table SET @j = @i, @i = @i + 1

PRINT '@i = ' + CAST(@i AS VARCHAR) + ', @j = ' + CAST(@j AS VARCHAR)

SELECT @i = 1, @j = 0

UPDATE @Table SET @i = @i + 1, @j = @i

PRINT '@i = ' + CAST(@i AS VARCHAR) + ', @j = ' + CAST(@j AS VARCHAR)

SELECT @i = 1, @j = 0

UPDATE @Table SET @i = @j + 1, @j = @i

PRINT '@i = ' + CAST(@i AS VARCHAR) + ', @j = ' + CAST(@j AS VARCHAR)

SELECT @i = 1, @j = 0

UPDATE @Table SET @i = @j, @j = @i

PRINT '@i = ' + CAST(@i AS VARCHAR) + ', @j = ' + CAST(@j AS VARCHAR)

SET NOCOUNT OFF;

结果:

@i = 2, @j = 1

@i = 2, @j = 2

@i = 1, @j = 1

@i = 0, @j = 0

3) 字段之间, 并行执行

SET NOCOUNT ON;

DECLARE @Table TABLE