如何在 SQLite 上使用 CTE 和更新/删除?

本文介绍了如何在 SQLite 上使用 CTE 和更新/删除?的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

SQLite 现在有 CTE，文档 说您可以将它用于插入、更新和删除查询——但是仅给出 select 语句的示例.

SQLite now has CTEs, and the documentation says you can use it with insert, update and delete queries -- but only gives examples of select statements.

我可以通过 insert-select 弄清楚 CTE 如何应用于插入；但是我们如何在没有 from 子句的更新或删除中使用它们?

I can figure out how CTEs apply to inserts, via insert-select; but how can we use them in update or delete, where there is no from-clause?

推荐答案

可以在子查询中使用 CTE:

CTEs can be used in subqueries:

WITH NewNames(ID, Name) AS (...) UPDATE MyTable SET Name = (SELECT Name FROM NewNames WHERE ID = MyTable.ID); WITH IDsToDelete AS (...) DELETE FROM MyTable WHERE ID IN IDsToDelete;