résultat différent de SELECT et SELECT de l'intérieur d'une VUE
Question
Résultat de l'instruction SELECT est différent du résultat de SELECT VIEW à l'intérieur. Comment résoudre le problème et obtenir le même résultat en vue?
Tableau Actions:
+--+---------+--------------+-----------+------+
|id|person_id|action_type_id|currency_id|sum |
+--+---------+--------------+-----------+------+
|1 |1 |1 |1 | 1.00 |
|2 |1 |1 |1 | 5.00 |
|3 |1 |1 |2 |10.00 |
|4 |1 |2 |1 | 2.00 |
|5 |2 |1 |1 |20.00 |
|6 |2 |2 |2 | 5.00 |
+--+---------+--------------+-----------+------+
sélectionnez:
SELECT person_id AS p, currency_id AS c,
(
CAST(
COALESCE(
(SELECT SUM(sum) FROM actions WHERE action_type_id=1 AND person_id=p AND currency_id=c)
, 0)
AS DECIMAL(11,2)) -
CAST(
COALESCE(
(SELECT SUM(sum) FROM actions WHERE action_type_id=2 AND person_id=p AND currency_id=c)
, 0)
AS DECIMAL(11,2))
) AS sum
FROM actions
GROUP BY currency_id, person_id
ORDER BY person_id, currency_id;
Résultat:
+--+--+------+
|p |c |sum |
+--+--+------+
|1 |1 | 4.00 |
|1 |2 |10.00 |
|2 |1 |20.00 |
|2 |2 |-5.00 |
+--+--+------+
sélectionnez vue de l'intérieur:
CREATE VIEW p_sums AS
SELECT person_id AS p, currency_id AS c,
(
CAST(
COALESCE(
(SELECT SUM(sum) FROM actions WHERE action_type_id=1 AND person_id=p AND currency_id=c)
, 0)
AS DECIMAL(11,2)) -
CAST(
COALESCE(
(SELECT SUM(sum) FROM actions WHERE action_type_id=2 AND person_id=p AND currency_id=c)
, 0)
AS DECIMAL(11,2))
) AS sum
FROM actions
GROUP BY currency_id, person_id
ORDER BY person_id, currency_id;
SELECT * FROM p_sums;
Résultat:
+--+--+------+
|p |c |sum |
+--+--+------+
|1 |1 |29.00 |
|1 |2 |29.00 |
|2 |1 |29.00 |
|2 |2 |29.00 |
+--+--+------+
La solution
Pouvez-vous pas:
SELECT person_id AS p, currency_id AS c, SUM(CASE action_Type_id WHEN 1 THEN sum WHEN 2 THEN -sum END) as sum
FROM actions
GROUP BY currency_id, person_id
ORDER BY person_id, currency_id;
i.e.. se débarrasser des sous-requêtes, et juste construire une somme unique vers le haut (faisant action_type_id 2 valeurs négatives)
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