如何在SQLite的更新/删除中使用CTE? [英] How to use CTE's with update/delete on SQLite?
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问题描述
SQLite现在具有CTE,并且文档表示您可以将其与插入,更新和删除查询一起使用-但
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找出CTE如何应用于插入。但是如何在没有从句的情况下如何在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
CTE可以在子查询中使用:
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;
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