SQL : count(*) NULL
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Stef60
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257
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Stef60 Messages postés 257 Statut Membre -
Stef60 Messages postés 257 Statut Membre -
Bonjour,
j'ai un souci avec une requete SQL
voici la requete:
SELECT count(DISTINCT a.id), count(DISTINCT b.id) , count(DISTINCT c.id), count(DISTINCT d.id)
FROM
(SELECT id FROM table WHERE prj_id="18" AND status="10") a,
(SELECT id FROM table WHERE prj_id="18" AND status="15") b,
(SELECT id FROM table WHERE prj_id="18" AND status="20") c,
(SELECT id FROM table WHERE prj_id="18" AND status="40") d
Mon souci c'est que si une des requetes de la clause FROM (a->d) ne retourne aucune valeur
alors tous mes count sont egale a 0
Comment contourner ce probleme?
D'avance merci.
j'ai un souci avec une requete SQL
voici la requete:
SELECT count(DISTINCT a.id), count(DISTINCT b.id) , count(DISTINCT c.id), count(DISTINCT d.id)
FROM
(SELECT id FROM table WHERE prj_id="18" AND status="10") a,
(SELECT id FROM table WHERE prj_id="18" AND status="15") b,
(SELECT id FROM table WHERE prj_id="18" AND status="20") c,
(SELECT id FROM table WHERE prj_id="18" AND status="40") d
Mon souci c'est que si une des requetes de la clause FROM (a->d) ne retourne aucune valeur
alors tous mes count sont egale a 0
Comment contourner ce probleme?
D'avance merci.
3 réponses
-
j'ai trouvé la solution.
SELECT a.cnt
, b.cnt
, c.cnt
, d.cnt
FROM ( SELECT COUNT(DISTINCT id) AS cnt
FROM matable
WHERE prj_id='18'
AND STATUS='10'
) AS a
, ( SELECT COUNT(DISTINCT id) AS cnt
FROM matable
WHERE prj_id='18'
AND STATUS='15'
) AS b
, ( SELECT COUNT(DISTINCT id) AS cnt
FROM matable
WHERE prj_id='18'
AND STATUS='20'
) AS c
, ( SELECT COUNT(DISTINCT id) AS cnt
FROM matable
WHERE prj_id='18'
AND STATUS='40'
) AS d -
-
J'ai essayé avec ca:
....
(SELECT id IS NOT NULL FROM table WHERE prj_id="18" AND status="10") a,
....
et ca me repond "Unknown column 'a.id' in 'field list'"
