Merlin,
>I just discovered, that I do have some old rows I do not need anymore.
>A result from forgeting to empty the table before starting to go into
production :-)
>However, I do try to find the rows which are not asociated with
another table in
>order to delete them. I have 2 tables: table1 and table2
>table1 has the key: "ID"
>table2 has the subkey "table1_id"
To retrieve table1 rows for which there is no table2 row with a
table1_id value matching a table1.id value, you want a join netween the
two tables where table2.table1_id is null, something like...
SELECT id
FROM table1
INNER JOIN table2 ON table1.id=table2.table1_id
WHERE table2.table1_id IS NULL;
PB
-----
Merlin wrote:
> Hi there,
>
> I just discovered, that I do have some old rows I do not need anymore.
> A result from forgeting to empty the table before starting to go into
> production :-)
> However, I do try to find the rows which are not asociated with
> another table in order to delete them.
> I have 2 tables:
> table1 and table2
>
> table1 has the key: "ID"
> table2 has the subkey "table1_id"
>
> Now I would like to delete all rows in table1 which are not listed in
> table2 with an id.
> I tried:
> SELECT
> t1.*
> FROM
> table1 as t1,
> table2 as t2
> WHERE
> t1.ID != t2.table1_id
>
> But this returns hundreds of thousends of results.
> I also tryed to group by t1.ID, but it did not help
>
> Does anybody have a good idea how to get rid of those rows?
>
> Thanx, Merlin
>
> PS: Thanx for the answer for the question with full text search! That
> worked excellent!
>
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