>
>
> select case when t3.date='xxxx' then
> select * from table1
> else
> select * from table 2
> from table3 t3 where t3.date='xxxxx'
>
> Problem is that I have to do it in Plain SQL.
you problem is not quite clear.
do you want to output all rows from table1 (or table2)
for each row of table3?
or does table2 only have one row with date='xxxxx' ?
is 'xxxx' the same date as 'xxxxx' in your example?
if so, how can table2's columns be selected.
are you looking for something like:
select * from table1
where (select date from table3)='xxxx'
UNION ALL
select * from table2
where (select date from table3)<>'xxxx'
maybe little bit more readable form:
select *
from table1
where exists (select 1 from table3 where date = 'xxxx')
union all
select *
from table2
where exists (select 1 from table3 where date = 'xxxx');
it's possible with one big disadvantage. This query will do seq scan
both tables and it can be slow on big tables.
Regards
Pavel Stehule
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