I'm beginning in postgres and I have an issue regarding multiple select case in a select query.
bd_david=> select * from edt_sem;
code_module | groupe | week | day | hour | room
-------------+----------+------+-----+--------+-------
M3106 | INFOFCAS | 1 | 1 | 1 | O104
M3105 | INFOFCAS | 1 | 1 | 5 | O104
M3106 | INFOFCAS | 2 | 1 | 1 | O104
(3 rows)
What I want to do is to create a function that only show rows of a certain week and for that I am using this function :
CREATE or REPLACE function show_edt(IN paramSem numeric)
RETURNS TABLE(module varchar, groupe varchar, week numeric, day text, hour text, room varchar) AS
$$
BEGIN
RETURN QUERY
SELECT e.code_module,
e.groupe,
e.sem,
(SELECT CASE
WHEN e.jour = 1 THEN 'Monday'
WHEN e.jour = 2 THEN 'Tuesday'
WHEN e.jour = 3 THEN 'Wednesday'
WHEN e.jour = 4 THEN 'Thursday'
WHEN e.jour = 5 THEN 'Friday'
END "JOUR"
FROM edt_sem WHERE edt_sem.sem = paramSem [ LIMIT 1... ? Don't know ] ),
(SELECT CASE
WHEN heured = 1 THEN '9h'
WHEN heured = 2 THEN '10h'
WHEN heured = 3 THEN '11h'
WHEN heured = 4 THEN '12h'
WHEN heured = 5 THEN '14h'
WHEN heured = 6 THEN '15h'
WHEN heured = 7 THEN '16h'
WHEN heured = 8 THEN '17h'
END "HEURE"
FROM edt_sem WHERE edt_sem.sem = paramSem [ LIMIT 2 ?? don't know.. ]),
e.salle
FROM edt_sem e where e.sem = paramSem;
END;
$$ LANGUAGE plpgsql;
It works well for ONE row :
select * from afficher_edt(2);
module | groupe | week | day | hour | room
--------+----------+---------+-------+-------+-------
M3106 | INFOFCAS | 2 | Monday| 9h | O104
(1 row)
But I have issue for more than one row :
bd_david=> select * from afficher_edt(1);
module | groupe | week | day | hour | room
--------+----------+---------+-------+-------+-------
M3106 | INFOFCAS | 1 | Lundi | 9h | O104
M3105 | INFOFCAS | 1 | Lundi | 9h /!\| O104
/!\ It should have been displayed 14h instead of 9h
EDIT : The error message :
bd_david=> select * from show_edt(1);
ERROR: more than one row returned by a subquery used as an expression
CONTEXT: PL/pgSQL function afficher_edt(numeric) line 3 at RETURN QUERY
Well I get more or less why I got this error : it's because there are two rows fetched by my select case for different hours but I don't know how to get rid of it.. :/
CREATE or REPLACE function show_edt(IN paramSem numeric)
RETURNS TABLE (
module varchar, groupe varchar, week numeric,
day text, hour text, room varchar
) AS $$
BEGIN
RETURN QUERY
SELECT
e.code_module,
e.groupe,
e.sem,
CASE e.jour
WHEN 1 THEN 'Monday'
WHEN 2 THEN 'Tuesday'
WHEN 3 THEN 'Wednesday'
WHEN 4 THEN 'Thursday'
WHEN 5 THEN 'Friday'
END as "JOUR",
CASE heured
WHEN 1 THEN '9h'
WHEN 2 THEN '10h'
WHEN 3 THEN '11h'
WHEN 4 THEN '12h'
WHEN 5 THEN '14h'
WHEN 6 THEN '15h'
WHEN 7 THEN '16h'
WHEN 8 THEN '17h'
END as "HEURE"
e.salle
FROM edt_sem e
where e.sem = paramSem;
END;
$$ LANGUAGE plpgsql;
You don't need plpgsql for this. Just sql
CREATE or REPLACE function show_edt(IN paramSem numeric)
RETURNS TABLE (
module varchar, groupe varchar, week numeric,
day text, hour text, room varchar
) AS $$
SELECT
e.code_module,
e.groupe,
e.sem,
CASE e.jour
WHEN 1 THEN 'Monday'
WHEN 2 THEN 'Tuesday'
WHEN 3 THEN 'Wednesday'
WHEN 4 THEN 'Thursday'
WHEN 5 THEN 'Friday'
END as "JOUR",
CASE heured
WHEN 1 THEN '9h'
WHEN 2 THEN '10h'
WHEN 3 THEN '11h'
WHEN 4 THEN '12h'
WHEN 5 THEN '14h'
WHEN 6 THEN '15h'
WHEN 7 THEN '16h'
WHEN 8 THEN '17h'
END as "HEURE"
e.salle
FROM edt_sem e
where e.sem = paramSem;
$$ LANGUAGE sql;