Re: How to delete multiple records

On Thu, Sep 14, 2006 at 03:07:35PM +0900, Javanesevn wrote:
> Dear all,
>
> I execute this query on below:
>
> delete from PRODUCT
> where exists (
> select
> product_id, item_id
> from PRODUCT
> where
> research_date < '2006-01-01'
> )
> this query deleted all records data in PRODUCT table. The subquery
> return only some records.
> Tell me about other idea? and What's wrong from this query.

The easiest way is to do it like this:

delete from PRODUCT
where research_date < '2006-01-01'

But if you really want to use a subquery, you want to relate it to the
current record:

delete from PRODUCT
where product_in in (
select product_id
from PRODUCT
where research_date < '2006-01-01'
)

In your example you just test if some records exist. They allways do, so
the where clause evaluates to true for every row

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"Nothing is as subjective as reality"
Reinoud van Leeuwen reinoud(dot)v(at)n(dot)leeuwen(dot)net
http://www.xs4all.nl/~reinoud
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