Re: [GENERAL] question about join

[Ottavio Campana]

Osvaldo Kussama ha scritto:

 To further explain, the following query selects both the rows from the join
where id_ref_first_tab has the desired value and default_value = true, while
I want to select the row corresponding to default_value = true only in case
no row corresponding to id_ref_first_tab exists.

 select * from second_table join third_table on second_table.id =
third_table.id_ref_second_tab where id_ref_first_tab = 1 or default_value =
true;

 I hope I've been clear enough...

Try:
select * from second_table join third_table on second_table.id =
third_table.id_ref_second_tab
where id_ref_first_tab = 1 or (id_ref_first_tab <> 1 and default_value = true);

I don't know if it is possible, but if it could, it would be great.

--
Non c'e' piu' forza nella normalita', c'e' solo monotonia.

it's not what I want, because it can return two rows, while I want only one row back, checking the first condition and optionally the second one only if the first one is not matched.

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