当另一个表中不存在匹配项时，从SQLite表中删除行 [英] Deleting rows from SQLite table when no match exists in another table

问题描述

我需要从SQLite表中删除行，这些行的ID在另一个表中不存在. SELECT语句返回正确的行:

I need to delete rows from an SQLite table where their row IDs do not exist in another table. The SELECT statement returns the correct rows:

SELECT * FROM cache LEFT JOIN main ON cache.id=main.id WHERE main.id IS NULL;

但是，delete语句从SQLIte生成错误:

However, the delete statement generates an error from SQLIte:

DELETE FROM cache LEFT JOIN main ON cache.id=main.id WHERE main.id IS NULL;

错误是: SQLite错误1-靠近左":语法错误.还有其他可以使用的语法吗?

The error is: SQLite Error 1 - near "left": syntax error. Is there another syntax I could use?

推荐答案

SQLite显然不支持使用delete语句进行联接，正如您在

SQLite apparently doesn't support joins with the delete statement, as you can see on the Syntax diagrams. You should however be able to use a subquery to delete them.

即.

DELETE FROM cache WHERE id IN
(SELECT cache.id FROM cache LEFT JOIN main ON cache.id=main.id WHERE main.id IS NULL);

(未经测试)

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