Question

我正在尝试从不同的表中复制数据，同时保持彼此之间的不同链接。

我桌子的简化结构：

timetable (pk INT PRIMARY KEY IDENTITY(1,1), name VARCHAR(50))
timetable_group (pk INT PRIMARY KEY IDENTITY(1,1), timetable_fk INT, name VARCHAR(50))
timetable_class (pk INT PRIMARY KEY IDENTITY(1,1), timetable_fk INT, timetable_group_fk INT, name VARCHAR(50))

我的目标是能够在timetable_group和timetable_class中复制时间表条目及其所有相关条目。

获得@new_timetable_fk INSERT和@@IDENTITY之后，我遇到了问题：

如何从timetable_group复制并取回插入的pK，以便在复制timetable_class时能够使用它们？

我试过用这个：

-- This is a parameter to my code
DECLARE @timetable_fk INT
SET @timetable_fk = 1

-- start of my Stored Procedure

-- this will hold my new timetable_fk
DECLARE @new_timetable_fk INT

-- this will hold the old and new pks of timetable_group
-- so we can join on it
DECLARE @timetable_group_link_pks TABLE (new_pk INT, old_pk INT)

-- copy the timetable entry
INSERT INTO timetable (name)
SELECT LEFT(name + ' copy', 50)
FROM timetable
WHERE pk = @timetable_fk

-- get the pk of the newly inserted value
SET @new_timetable_fk = @@IDENTITY


-- copy timetable_group
INSERT INTO timetable_group (timetable_fk, name)
-- This return the error `The multi-part identifier "g.pk" could not be bound` 
OUTPUT inserted.pk, g.pk
    INTO @timetable_group_link_pks
SELECT @new_timetable_fk, g.name
FROM timetable_group g
WHERE g.timetable_fk = @timetable_fk

-- copy timetable class
INSERT INTO timetable_class (timetable_fk, timetable_group_fk, name)
SELECT @new_timetable_fk, gl.new_pk, c.name
FROM timetable_class c
    JOIN @timetable_group_link_pks gl ON c.timetable_group_fk = gl.old_pk
WHERE c.timetable_fk = @timetable_fk

但它不起作用，因为我不能在OUTPUT子句中使用g.pk。

MSDN告诉我们OUTPUT子句应该按我的意愿工作，但TSQL不接受它。

知道如何解决这个问题吗？

Answer 1

你应该使用Merge语句和Output子句而不是直接插入，请参阅Link

Answer 2

“输出”中不存在g.pk，因为“插入”和选择查询不会自动连接。

你可以跳过@timetable_group_link_pks表和OUTPUT的东西，你不需要它。

这应该有效：

-- copy timetable_group
INSERT INTO timetable_group (timetable_fk, name)
SELECT @new_timetable_fk, g.name
FROM timetable_group g
WHERE g.timetable_fk = @timetable_fk

-- copy timetable_class
INSERT INTO timetable_class (timetable_fk, timetable_group_fk, name)
SELECT @new_timetable_fk, c.timetable_group_fk, c.name
FROM timetable_class c
join timetable_group g on g.timetable_fk = c.timetable_fk
WHERE c.timetable_fk = @timetable_fk and g.pk = @timetable_fk

从table1复制条目然后使用table1外键复制table2中的条目

2 个答案: