使用内部连接更新 Postgresql答案

【问题标题】：Update with inner join Postgresql使用内部连接更新 Postgresql
【发布时间】：2017-05-22 17:35:08
【问题描述】：

因为执行此更新不适用于 where 子句？更新对我来说都是如此。

UPDATE ventas SET eav_id = 7 
FROM ventas AS A
inner join ventasDetalle AS e on A.act_id = e.act_id and e.exp_id = A.exp_id
where a.eav_id = 1

【问题讨论】：

标签： postgresql postgresql-9.4

【解决方案1】：

update ventas a
set eav_id = 7 
from ventasDetalle e
where a.eav_id = 1 and (a.act_id, a.exp_id) = (e.act_id, e.exp_id)

【讨论】：

【解决方案2】：

Postgresql UPDATE 语法是：

[ WITH [ RECURSIVE ] with_query [, ...] ]
UPDATE [ ONLY ] table [ [ AS ] alias ]
    SET { column = { expression | DEFAULT } |
          ( column [, ...] ) = ( { expression | DEFAULT } [, ...] ) } [, ...]
    [ FROM from_list ]
    [ WHERE condition | WHERE CURRENT OF cursor_name ]
    [ RETURNING * | output_expression [ [ AS ] output_name ] [, ...] ]

所以我想你想要：

UPDATE ventas AS A 
SET eav_id = 7
FROM ventasDetalle AS e
WHERE (A.act_id = e.act_id and e.exp_id = A.exp_id)

【讨论】：