Re: count syntax

Is this a TODO bug?

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Tom Lane wrote:
> Patrick Welche <prlw1(at)newn(dot)cam(dot)ac(dot)uk> writes:
> > What is the difference between the following?
>
> > transatlantic=# select count(*) from trans;
>
> This is a SQL-spec-mandated special case meaning "count the number of rows".
>
> > transatlantic=# select count(trans.flowindex) from trans;
>
> This counts the number of non-null values of trans.flowindex. Also
> per spec.
>
> > transatlantic=# select count(trans.*) from trans;
> ERROR: Memory exhausted in AllocSetAlloc(204)
>
> This syntax is not legal per SQL spec. Postgres interprets it as a
> command to count the number of non-null values of "trans.*", which in
> this context is taken as being a whole-row variable. Unfortunately the
> present implementation of whole-row variables leaks memory ...
>
> I don't believe that a whole-row variable will ever be null, so the
> end result is the same as count(*). You may as well spell it in the
> spec-approved fashion.
>
> regards, tom lane
>
>
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