使用FULL JOIN连接两个表

Question

我有两张表master1和master2：

insert into master1 
(name,address,books,laptop,id,college) values
(ratan,mg road,rajbook,hp,id334,xxx)
(sham,r t nagar,malbook,ibm,id335,xxx)
(ram,shiva road,kalbook,hp,id336,xxx)
(farooq,uday road,rabook,hp,id337,xxx)
(sharukh,kr road,kambook,sony,id338,xxx)

insert into master2
(nam,lappy,idd,coll) values
(ratan,hp,877,ratan college)
(ram,sony,877,ram college)

我想：

select name, address, books, laptop, id, college, nam, lappy
  from master1 LEFT JOIN master2
 where master1.college=master2.coll

输出应为：

(name,address,books,laptop,id,college,nam,lappy
(ratan,mg road,rajbook,hp,id334,xxx,keshav,hp)
(sham,r t nagar,malbook,ibm,id335,xxx,null,null)
(ram,shiva road,kalbook,hp,id336,xxx,null.null)
(farooq,uday road,rabook,hp,id337,xxx,null,null)
(sharukh,kr road,kambook,sony,id338,xxx,ram,sony)

Answer 1

WHERE不正确，而您遗漏了ON条款的JOIN部分。

select name,address,books,laptop,id,college,nam,lappy
from master1
left join master2 on master1.college = master2.coll

Answer 2

使用ON

SELECT name,address,books,laptop,id,college,nam,lappy
FROM master1
LEFT OUTER JOIN master2
ON master1.college = master2.coll

Answer 3

Select name
      ,address
      ,books
      ,laptop
      ,id
      ,college
      ,nam
      ,lappy
From master1
LEFT JOIN master2 ON 
      master1.college=master2.coll

你的左连接错了我格式化了这个

Joins Tutorial

LEFT JOIN and RIGHT JOIN Optimization

您的输出如下

Working SQL Fiddle