Обсуждение: update one table with another

On Apr 20, 2009, at 10:34 PM, Matthew Pugsley wrote:

> I've solved it.
>
> I just used a subselect. Worked very quickly. I had a lot of trouble
> with subqueries when I first started databases with MySQL. So I have
> been afraid of them.
>
> update entities
> set customer_status = select(customer_status from
> entity_dimension_update where entities.entity_id =
> entity_dimension_update.entity_id);

What a peculiar way to write a subquery, with the braces like that.
Normally you'd put the opening brace before the select statement, not
after it.

>  Worked almost instantly.

Alternatively you could use UPDATE...FROM:

update entities
set customer_status = t2.customer_status
from entity_dimension_update as t2
where entity_id = t2.entity_id

Alban Hertroys

--
If you can't see the forest for the trees,
cut the trees and you'll see there is no forest.


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