Mehrere Lösch in einer einzigen Abfrage

Question

FROM Table1 DELETE WHERE ConditionID = ConditionID;?

DELETE FROM Table2 WHERE ConditionID=?ConditionID;

DELETE FROM Table3 WHERE ConditionID=?ConditionID;

ConditionID ist eine Spalte in Tabelle 1, Tabelle 2, Tabelle 3, statt läuft 3 mal einzeln, gibt es eine Möglichkeit, alle drei in einer einzigen Abfrage zu laufen (in mysql)?

Answer 1

Wenn der ConditionID ist das gleiche für alle drei Tabellen, sollen Sie in der Lage sein, die Mehrere Tabelle löschen Syntax :

DELETE Table1, Table2, Table3
FROM   Table1
JOIN   Table2 ON (Table2.ConditionID = Table1.ConditionID)
JOIN   Table3 ON (Table3.ConditionID = Table2.ConditionID)
WHERE  Table1.ConditionID = ?;

Testfall:

CREATE TABLE Table1 (id int, ConditionID int);
CREATE TABLE Table2 (id int, ConditionID int);
CREATE TABLE Table3 (id int, ConditionID int);

INSERT INTO Table1 VALUES (1, 100);
INSERT INTO Table1 VALUES (2, 100);
INSERT INTO Table1 VALUES (3, 200);

INSERT INTO Table2 VALUES (1, 100);
INSERT INTO Table2 VALUES (2, 200);
INSERT INTO Table2 VALUES (3, 300);

INSERT INTO Table3 VALUES (1, 100);
INSERT INTO Table3 VALUES (2, 100);
INSERT INTO Table3 VALUES (3, 100);

Ergebnis:

DELETE Table1, Table2, Table3
FROM   Table1
JOIN   Table2 ON (Table2.ConditionID = Table1.ConditionID)
JOIN   Table3 ON (Table3.ConditionID = Table2.ConditionID)
WHERE  Table1.ConditionID = 100;

SELECT * FROM Table1;
+------+-------------+
| id   | ConditionID |
+------+-------------+
|    3 |         200 |
+------+-------------+
1 row in set (0.00 sec)

SELECT * FROM Table2;
+------+-------------+
| id   | ConditionID |
+------+-------------+
|    2 |         200 |
|    3 |         300 |
+------+-------------+
2 rows in set (0.00 sec)

SELECT * FROM Table3;
Empty set (0.00 sec)

Answer 2

Ich weiß nicht, was Ihr Schema aussieht, aber wenn Sie InnoDB verwenden oder eine ähnliche Tabelle Motor für Ihre Tabellen und Fremdschlüssel haben, können Sie Bedingungen festlegen, die Einträge verursachen abgeleitet gelöscht werden, wenn ein Elternteil Eintrag ist gelöscht. Siehe http://dev.mysql.com /doc/refman/5.1/en/innodb-foreign-key-constraints.html für weitere Informationen auf das.

Answer 3

Nope. ConditionID is separate in each one—just because it has the same name doesn't mean it's the same column. If you fully qualify the names, you'll be able to see it better:

DELETE FROM Table1 WHERE Table1.ConditionID=?ConditionID;

DELETE FROM Table2 WHERE Table2.ConditionID=?ConditionID;

DELETE FROM Table3 WHERE Table3.ConditionID=?ConditionID;

Answer 4

You can delete rows from multiple tables by just using mysql "delete" query.Consider,you've two tables profile and books.

Profile table consists,

• id
• name

books table consists,

• pid
• book
• price

You can delete records from these two table for particular id by using this query,

delete profile,books from profile,books where profile.id=18 and profile.id=books.pid;