更新和左外部联接语句 | 更新和左外部联接语句

本文介绍了更新和左外部联接语句的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

我有两个具有关联的表格，并且我想更新表A中的一个字段.是否可以将更新和联接合并到同一查询中?我用谷歌搜索，但没有找到任何可行的解决方案?

I have two tabels with a relation and I want to update a field in table A. Is it possible to combine update and join in the same query? I googled it but didnt find any working solution?

UPDATE md SET md.status = '3'
FROM pd_mounting_details AS md
LEFT OUTER JOIN pd_order_ecolid AS oe ON md.order_data = oe.id

我正在使用MS SQL

I'm using MS SQL

推荐答案

Update t
SET
       t.Column1=100
FROM
       myTableA t
LEFT JOIN
       myTableB t2
ON
       t2.ID=t.ID

将myTableA替换为表名，并将Column1替换为列名.

Replace myTableA with your table name and replace Column1 with your column name.

此后，只需将LEFT JOIN移至tableB.在这种情况下，t只是myTableA的别名. t2是联接表的别名，在我的示例中为myTableB.如果您不喜欢使用t或t2，请使用您喜欢的任何别名-没关系-我只是喜欢使用那些别名.

After this simply LEFT JOIN to tableB. t in this case is just an alias for myTableA. t2 is an alias for your joined table, in my example that is myTableB. If you don't like using t or t2 use any alias name you prefer - it doesn't matter - I just happen to like using those.

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