Question

我有三个表，我想要从中检索值，我使用后面的查询给出了错误，有人能告诉我什么是错的吗？

SELECT a.VISITOR_TEXT,a.COMPANY_TEXT,a.CONTACT,a.PERSON_TO_MEET,a.DEPARTMENT_TEXT,a.FLOOR,b.BELONGING_T
YPE,b.BELONGING_TEXT ,a.INTIME, c.EXIT_TIME FROM tm_visitor a  LEFT JOIN tm_belonging b , tm_exit c ON a.ID=b.
BID AND a.ID=c.ID;

Answer 1

SELECT a.VISITOR_TEXT,a.COMPANY_TEXT,a.CONTACT,a.PERSON_TO_MEET,a.DEPARTMENT_TEXT,a.FLOOR,b.BELONGING_TYPE,b.BELONGING_TEXT ,a.INTIME, c.EXIT_TIME FROM tm_visitor a  
LEFT JOIN tm_belonging b ON a.ID=b.BID 
LEFT JOIN tm_exit c ON a.ID=c.ID;

Answer 2

这就是你要找的东西：

SELECT  a.VISITOR_TEXT,
        a.COMPANY_TEXT,
        a.CONTACT,
        a.PERSON_TO_MEET,
        a.DEPARTMENT_TEXT,
        a.FLOOR,
        b.BELONGING_TYPE,
        b.BELONGING_TEXT,
        a.INTIME,
        c.EXIT_TIME 
FROM    tm_visitor a  
        LEFT JOIN tm_belonging b ON b.BID = a.id
        LEFT JOIN tm_exit c ON c.ID = a.ID

Answer 3

您不能将,与联接语法一起使用。仅在from语法中。使用

SELECT  a.VISITOR_TEXT, a.COMPANY_TEXT,a.CONTACT, a.PERSON_TO_MEET,a.DEPARTMENT_TEXT, a.FLOOR,b.BELONGING_TYPE,b.BELONGING_TEXT, a.INTIME, c.EXIT_TIME 
FROM tm_visitor a  
LEFT JOIN tm_belonging b  ON a.ID=b.BID
left join tm_exit c ON a.ID=c.ID

如何在mysql中连接三个或更多表

3 个答案: