plpgsql-fct. fails on NULL in record variables
Hi all,
I'm currently coding some functions in plpgsql for generating
reports out of records in a table. Problem is: NULL values in
records make the complete function fail.
Here is a simple test case (original is more complex with a multi-
table query in the for qres in select... part):
create table test(
id serial,
descr char(4),
data int
);
insert into test (descr, data) values ('set1', 15);
-- record 2 does not have a data value --
insert into test (descr) values ('set2');
create function report(int) returns text as '
declare
qres record;
report text;
begin
for qres in
select descr, data from test where id=$1
loop
report:=qres.descr||'': ''||qres.data;
end loop;
return report;
end;'
language 'plpgsql';
now test the function in psql:
test=> select report(1);
report
----------
set1: 15
(1 row)
test=> select report(2);
report
--------
(1 row)
while what I want it to return in the second case is this:
report
--------
set2:
(1 row)
'set2: NULL' would be ok as well.
How can I achieve this?
Regards,
Daniel
concatenating a NULL value to a string will return NULL.
SELECT NULL||'Stringggg';
?column?
----------
(1 row)
There's a fonction called coalesce that replaces NULL values with a
specified value it can be usefull:
SELECT coalesce(NULL,'') || ' Stringgggg';
?column?
-------------
Stringgggg
(1 row)
SELECT coalesce('A','') || ' Stringgggg';
?column?
--------------
A Stringgggg
(1 row)
HTH
Najib.
----- Original Message -----
From: "Daniel Martini" <dmartini@uni-hohenheim.de>
To: <pgsql-general@postgresql.org>
Sent: Friday, September 24, 2004 11:33 AM
Subject: [GENERAL] plpgsql-fct. fails on NULL in record variables
Show quoted text
Hi all,
I'm currently coding some functions in plpgsql for generating
reports out of records in a table. Problem is: NULL values in
records make the complete function fail.
Here is a simple test case (original is more complex with a multi-
table query in the for qres in select... part):create table test(
id serial,
descr char(4),
data int
);insert into test (descr, data) values ('set1', 15);
-- record 2 does not have a data value --
insert into test (descr) values ('set2');create function report(int) returns text as '
declare
qres record;
report text;
begin
for qres in
select descr, data from test where id=$1
loop
report:=qres.descr||'': ''||qres.data;
end loop;
return report;
end;'
language 'plpgsql';now test the function in psql:
test=> select report(1);
report
----------
set1: 15
(1 row)test=> select report(2);
report
--------(1 row)
while what I want it to return in the second case is this:
report
--------
set2:
(1 row)'set2: NULL' would be ok as well.
How can I achieve this?
Regards,
Daniel---------------------------(end of broadcast)---------------------------
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