本文介绍了sqlite LEFT OUTER JOIN 多个表的处理方法,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
在这个例子中,我们在 SQLite 数据库中有 3 个相关的表:
In this example we have 3 related tables on a SQLite database:
CREATE TABLE test1 ( c1 integer, primary key (c1) ); CREATE TABLE test2 ( c1 integer, c2 integer, primary key (c1, c2) ); CREATE TABLE test3 ( c2 integer, c3 integer, primary key (c2) );现在我需要加入所有表:
Now I need to join all tables:
test1 -> test2 (with c1 column) test2 -> test3 (with c2 column).我已经尝试过这个解决方案,但它没有运行:
I have tried this solution but it doesn't run:
SELECT * FROM test1 a LEFT OUTER JOIN test2 b LEFT OUTER JOIN test3 c ON c.c2 = b.c2 ON b.c1=a.c1它给了我一个错误:ON"附近:语法错误.
有什么帮助吗?
推荐答案这是 ON 语句的一个简单错误.这符合 SQL 标准:
This is a simple misplacement of your ON statement. This conforms to SQL standard:
SELECT * FROM test1 a LEFT OUTER JOIN test2 b ON b.c1=a.c1 LEFT OUTER JOIN test3 c ON c.c2=b.c2这在 进一步深入.
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