Michael Toews wrote:
> Now, I would like to group a summary of the strings in "sub", but they
> must be ordered alphabetically. Here I attempt the SQL:
> select commacat(sub), grp from aggr_test group by grp;
> However, on my system it will output the "commacat" column as:
> "one, two, three";"pom pom"
> "two, three, one";"la la"
> (notice that the items in the first column are ordered differently,
> since the input values were entered in non-alphabetically)
> This is where I get confused, since in the aggregate function, I have
> specified `SORTOP="<"`, which according to the documentation
> "must be equivalent to":
> SELECT sub FROM aggr_test ORDER BY sub USING <; -- LIMIT 1;
That's for things like min()/max() where you only want the first/last
value of some set. You want all of them.
You could accumulate the values in an array and then sort that with the
final-func that create aggregate supports.
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