Tom Lane wrote:
create function greatest(anyelement, anyelement) returns anyelement as 'select case when $1>$2 then $1 else $2 end' language sql;
Any chance of this making it into 7.4's contrib? Maybe with enough documentation to make it a tutorial for PostgreSQL's user functions?
> >> You do have to create several greatest() functions for different >> numbers of arguments, but not one for each datatype you want to >> handle. > > Insignificant, compared with the flexiblity.
I don't think it's worth putting in contrib, but for the archives:
create or replace function make_greatest() returns text as '
declare
v_args int := 32;
v_first text := ''create or replace function greatest(anyelement, anyelement) returns anyelement as ''''select case when $1 > $2 then $1 else $2 end'''' language ''''sql'''''';
v_part1 text := ''create or replace function greatest(anyelement'';
v_part2 text := '') returns anyelement as ''''select greatest($1, greatest($2'';
v_part3 text := ''))'''' language ''''sql'''''';
v_sql text;
begin
execute v_first;
for i in 3 .. v_args loop
v_sql := v_part1;
for j in 2 .. i loop
v_sql := v_sql || '',anyelement'';
end loop;
v_sql := v_sql || v_part2;
for j in 3 .. i loop
v_sql := v_sql || '',$'' || j::text;
end loop;v_sql := v_sql || v_part3;
execute v_sql; end loop; return ''OK''; end; ' language 'plpgsql';
select make_greatest();
Now you should have 31 "greatest" functions, accepting from 2 to 32 arguments. *Not* heavily tested, but seemed to work for me.
regression=# select greatest(112,2,3,4,5,6,7,8,9,10,1234,2,3,4,5,66,7,8,9,10,1,27,3,4,5,6,347,8,9,10,1,2);
greatest
----------
1234
(1 row)
I'll leave "least()" as an exercise for the reader ;-)
HTH,
Joe
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