删除...sqlite 中的左连接查询

Question

我正在使用 Xamarin Forms 开发 iOS 和 Android 应用程序。我有以下代码：

db2.Execute("DELETE w FROM Word AS w" +
            " LEFT JOIN WordSource AS ws ON ws.WordId = w.WordId" +
            " WHERE ws.WordId IS NULL");

但我一直在 w 附近遇到语法错误。有人可以让我知道我做错了什么吗？DELETE... JOIN...sqlite不支持查询吗？如果是这样，我怎样才能在sqlite中完成这段代码？

Answer 1

一种简单的方法是基于 a in 子句和带有左连接的子选择

db2.Execute( "DELETE  FROM Word WHERE id in (  
                SELECT id FROM Word as W  
                LEFT JOIN WordSource AS ws ON ws.WordId = w.WordId 
                WHERE ws.WordId IS NULL
              )");