Tom Lane writes:
> I expect what you are after is the ability to produce an 0-or-1
> numeric value from a bool field, so that you could do things like
> sum(boolfield::int) to count the number of true values in a column.
> I agree that we need such an operator (and I'm surprised no one's
> gotten round to contributing one).
Let's contribute one now ...
select count(*) from test4 where a = true;
select sum( case when a then 1 else 0 end ) from test4;
> But I don't agree that there
> should be an implicit, automatic conversion from bool to int; that
> defeats half of the error-checking value of having a separate type for
> truth values in the first place.
Definitely.
--
Peter Eisentraut Sernanders väg 10:115
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