Re: [SQL] SQL syntax for concating values in different rows together

[Joe Conway]

Elizabeth O'Neill's Office Mail wrote:

I have two tables in my database a complaint table and a resolution table.
One complaint may have several resolutions. I am trying to build a report
that will give me the complaint details and all the resolution descriptions
for a complaint in one text area/row (concated together).

At the moment it is repeating the complaint details for each resolution.

As someone else mentioned I think, you can use a plpgsql function. Here is a contrived example:

create table complaint(cid int, descr text);
insert into complaint values(1,'my #1 complaint');
insert into complaint values(2,'my #2 complaint');
create table resolution(rid int, cid int, res text);
insert into resolution values (1,1,'fixed it');
insert into resolution values (2,1,'really fixed it!');
insert into resolution values (3,2,'pbkbac again');

create or replace function my_concat(int) returns text as'
declare
ret text;
comp text;
rec record;
cntr int = 0;
begin
select into comp descr from complaint where cid = $1;
ret := ''Comp = '' || comp;
for rec in select res from resolution where cid = $1 loop
cntr := cntr + 1;
ret := ret || '': Res# '' || cntr::text || '' = '' || rec.res;
end loop;
return ret;
end;
' language 'plpgsql';

regression=# select my_concat(cid) from complaint;
my_concat
----------------------------------------------------------------------
Comp = my #1 complaint: Res# 1 = fixed it: Res# 2 = really fixed it!
Comp = my #2 complaint: Res# 1 = pbkbac again
(2 rows)

In the past I think I remember someone trying to solve this kind of problem with a custom aggregate, but the plpgsql approach is probably simpler.

HTH,

Joe


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