Pavel Stehule <[email protected]> writes:
> 2010/9/1 Tom Lane <[email protected]>:
>> Well, you can build your own version of array_agg with the same
>> implementation, except you mark the transition function as strict ...
> I am checking this now, and it is not possible - it needs a some
> initial value and there isn't possible to set a "internal" value.
Well, you can cheat a bit ...
regression=# create or replace function array_agg_transfn_strict(internal,
anyelement) returns internal as 'array_agg_transfn' language internal immutable;
CREATE FUNCTION
regression=# create aggregate array_agg_strict(anyelement) (stype = internal,
sfunc = array_agg_transfn_strict, finalfunc = array_agg_finalfn);
CREATE AGGREGATE
regression=# create or replace function array_agg_transfn_strict(internal,
anyelement) returns internal as 'array_agg_transfn' language internal strict
immutable;
CREATE FUNCTION
regards, tom lane
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