使用两个表上的连接更新查询

Question

我有customer和address桌子.

查询:

SELECT *
FROM addresses a,
     customers b
WHERE a.id = b.id

返回474条记录

对于这些记录,我想添加id的customer表成cid的address表.

示例:如果对于第一条记录,customer的id为9且id地址也为9,那么我想将9插入到地址表的cid列中.

我试过了:

UPDATE addresses a,
       customers b
SET a.cid = b.id
WHERE a.id = b.id

但这似乎不起作用.

Answer 1

这是Postgres UPDATE JOIN格式:

UPDATE address 
SET cid = customers.id
FROM customers 
WHERE customers.id = address.id

以下是其他变体:http://mssql-to-postgresql.blogspot.com/2007/12/updates-in-postgresql-ms-sql-mysql.html

Answer 2

在连接条件中使用表别名:

update addresses a
set cid = b.id 
from customers b 
where a.id = b.id