SQLite 是否支持“删除自"? [英] Does SQLite support "delete from from"

问题描述

这在 Microsoft SQL Server 的 T-SQL 上是有效的语法，但在 SQLite 中无效，是否有替代语法在 SQLite 中执行相同的操作?

This is valid syntax on Microsoft SQL Server's T-SQL, but not in SQLite, is there an alternative syntax that does the same in SQLite?

DELETE FROM something
FROM something
INNER JOIN combinations ON something.field1=combinations.field1
AND something.field2=combinations.field2
--optionally more criteria and/or more joins
WHERE combinations.field3=1234
--or anything really, just to show some criteria could be applied here also

推荐答案

一般情况下，将整个 join 移动到查找要删除行的主键的子查询中:

In the general case, move the entire join into a subquery that looks up the primary keys of the rows to be deleted:

DELETE FROM something
WHERE id IN (SELECT something.id
             FROM something
             JOIN combinations ON something.field1=combinations.field1
                              AND something.field2=combinations.field2
             WHERE combinations.something=1234)

如果您有复合主键，则可以使用 rowid 代替:

If you have a composite primary key, you can use the rowid instead:

DELETE FROM something
WHERE rowid IN (SELECT something.rowid
                FROM something
                JOIN combinations ON something.field1=combinations.field1
                                 AND something.field2=combinations.field2
                WHERE combinations.something=1234)

如果您有一个复合主键，并且您将表创建为 WITHOUT ROWID 表，您必须将连接重写为相关子查询:

If you have a composite primary key and you created the table as a WITHOUT ROWID table, you have to rewrite the join as a correlated subquery:

DELETE FROM something
WHERE EXISTS (SELECT 1
              FROM combinations
              WHERE field1 = something.field1
                AND field2 = something.field2
                AND field3 = 1234)

这篇关于SQLite 是否支持“删除自"?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！