informatique:sql
Différences
Ci-dessous, les différences entre deux révisions de la page.
Les deux révisions précédentesRévision précédenteProchaine révision | Révision précédenteDernière révisionLes deux révisions suivantes | ||
informatique:sql [16/02/2021 11:54] – [Insertions] cyrille | informatique:sql [13/04/2024 14:21] – cyrille | ||
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ou encore: sélection des lignes orphelines. | ou encore: sélection des lignes orphelines. | ||
- | === Question | + | **Question** |
I've got a SELECT query that I would like to transform as a DELETE query , | I've got a SELECT query that I would like to transform as a DELETE query , | ||
Ligne 84: | Ligne 84: | ||
Have you got a idea about it ??? | Have you got a idea about it ??? | ||
- | === Answer | + | **Answer** |
DELETE FROM Words WHERE IID NOT IN | DELETE FROM Words WHERE IID NOT IN | ||
( SELECT Words_ID FROM Feedbacks_has_Words ) | ( SELECT Words_ID FROM Feedbacks_has_Words ) | ||
+ | |||
+ | **Question** | ||
+ | |||
+ | Avec une base de données sqlite avec 2 tables. Une table contient les stations métérologiques et une table contient les mesures de températures journalières pour ces stations. Comment trouver en SQL les dates et les stations pour lesquelles il manque des mesures ? | ||
+ | |||
+ | **Réponse** | ||
+ | |||
+ | SELECT s.id, s.name AS nom_station, | ||
+ | FROM stations s | ||
+ | CROSS JOIN ( | ||
+ | SELECT DISTINCT measured_at FROM measures | ||
+ | ) AS dates | ||
+ | LEFT JOIN measures m ON s.id = m.station_id AND dates.measured_at = m.measured_at | ||
+ | WHERE m.station_id IS NULL | ||
+ | ORDER BY s.id, dates.measured_at; | ||
==== Insertions ==== | ==== Insertions ==== | ||
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REPLACE --> http:// | REPLACE --> http:// | ||
+ | |||
+ | |||
+ | **pour les accès concurrents avec SELECT FOR UPDATE en SQL** | ||
+ | * https:// | ||
+ | * https:// | ||
==== Supprimer doublons ==== | ==== Supprimer doublons ==== | ||
+ | https:// | ||
+ | |||
+ | Compter les doublons: | ||
+ | <code sql> | ||
+ | SELECT count(*) as DOUBLON, employee_id | ||
+ | FROM globalstatements | ||
+ | group by employee_id | ||
+ | having count(*) > 1 | ||
+ | limit 100000 | ||
+ | </ | ||
+ | |||
+ | Les supprimer: | ||
<code sql> | <code sql> | ||
delete G1 from globalstatements G1 | delete G1 from globalstatements G1 | ||
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==== MySQL Workbench ==== | ==== MySQL Workbench ==== | ||
+ | [[/ | ||
==== HeidiSQL ==== | ==== HeidiSQL ==== | ||
+ | https:// | ||
+ | |||
+ | HeidiSQL runs fine on Windows 8 and 10 (and on Windows 7 + 11 with some minor issues). | ||
==== Tora ==== | ==== Tora ==== | ||
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In addition to regular query and data browsing functionality, | In addition to regular query and data browsing functionality, | ||
+ | |||
+ | ==== DB Browser for SQLite ==== | ||
+ | |||
+ | https:// | ||
+ | |||
informatique/sql.txt · Dernière modification : 13/04/2024 14:22 de cyrille