Re: Inserting data of two other tables [Now deleting ...]

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Nabil Sayegh wrote:

| DELETE FROM a WHERE datum='17.07.1999'::date
~                            ^^^^^^^^^^^^
            This data is not in the "a" table, is in the b one. And the records I
need to remove are the ones from the b table. Will it work this way?


| AND NOT EXISTS (SELECT NULL FROM b WHERE b.field=a.field);

What does this part do? It selects rows where b.field and a.field are
not the same? And the "AND NOT EXISTS"? It inverts the query? I mean, if
the intraparenthesys part selects the rows where b.field <> a.field,
after you change the "sign", selecting the rows that DO have the
b.field=a.field?

I'm a bit confused...

Josep Sànchez
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