sqlite LEFT OUTER JOIN 多个表

Question

在这个例子中，我们在 SQLite 数据库中有 3 个相关表:

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)
);

现在我需要连接所有表:

 test1 -> test2 (with c1 column)          test2 -> test3 (with c2 column).

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 

它给我一个错误: 接近“ON”:语法错误。

有什么帮助吗？

Answer 1

这是您的 ON 语句的简单错位。这符合 SQL 标准:

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 further depth here. 中有解释