Question

我需要构建一个SQL查询，该查询必须能够在第一个表中插入数据，获取插入的ID，然后将其用作下表中的外键。

WITH inserted AS (
    INSERT INTO firstTable (name) VALUES ('somename') RETURNING id
)

SELECT * FROM inserted; -- this has the inserted id

INSERT INTO secondTable (name, foreign_id) VALUES ('someexternalname', ???)

那么如何在id插入中引用inserted中的secondTable？

Answer 1

您可以这样做：

WITH inserted AS (
    INSERT INTO firstTable (name) VALUES ('somename') RETURNING id
)

INSERT INTO secondTable (name, foreign_id)
SELECT
'someexternalname',
id
FROM inserted;

Answer 2

您已经完成了80％，完整的SQL是：

with inserted as (
 insert into first_table(name) values ('somename') returning id
)
insert into second_table(name, foreign_id) select 'someexternalname',id from inserted

Answer 3

您可以尝试以下方法：

INSERT INTO secondTable (name, foreign_id) VALUES ('someexternalname', (SELECT 
MAX (id) FROM firstTable))

在Postgres中引用多个插入事务中的插入ID

3 个答案: