多个左连接到单个表

Question

我有表的一大堆：

Table1: PersonID, A1, A2, A3, ... 

Table2: PersonID, B1, B2, B3, ... 

Table3: PersonID, C1, C2, C3, ... 

Table4: PersonID, D1, D2, D3, ... 

... 

表1是特殊的，因为它实际上包含所有个人（姓名和个人信息），但所有其他表几乎肯定缺少行（一个人根本没有参加那个活动）。

我想要做的是将所有表连接在一起（通过普通的PersonID），以便任何缺失的属性都会留空。所以，当然，我想用外连接。这是我试过的：

SELECT * 

FROM Table1, Table2, Table3, Table4, Table5, Table6 

LEFT OUTER JOIN Table2 ON Table1.PersonID = Table2.PersonID 
LEFT OUTER JOIN Table3 ON Table1.PersonID = Table3.PersonID 
LEFT OUTER JOIN Table4 ON Table1.PersonID = Table4.PersonID 
LEFT OUTER JOIN Table5 ON Table1.PersonID = Table5.PersonID 
LEFT OUTER JOIN Table6 ON Table1.PersonID = Table6.PersonID 

所有这一切都给我一个记忆超载。我想我不知道如何把所有桌子上的笛卡尔积放在一起，这一切都在窒息。有没有一个好的方法来做到这一点？

在此先感谢！

Answer 1

更改此：

SELECT * 

FROM Table1, Table2, Table3, Table4, Table5, Table6 

LEFT OUTER JOIN Table2 ON Table1.PersonID = Table2.PersonID 
LEFT OUTER JOIN Table3 ON Table1.PersonID = Table3.PersonID 
LEFT OUTER JOIN Table4 ON Table1.PersonID = Table4.PersonID 
LEFT OUTER JOIN Table5 ON Table1.PersonID = Table5.PersonID 
LEFT OUTER JOIN Table6 ON Table1.PersonID = Table6.PersonID 

这样：

SELECT * 

FROM Table1 
LEFT OUTER JOIN Table2 ON Table1.PersonID = Table2.PersonID 
LEFT OUTER JOIN Table3 ON Table1.PersonID = Table3.PersonID 
LEFT OUTER JOIN Table4 ON Table1.PersonID = Table4.PersonID 
LEFT OUTER JOIN Table5 ON Table1.PersonID = Table5.PersonID 
LEFT OUTER JOIN Table6 ON Table1.PersonID = Table6.PersonID 

是，哟服用的所有表的笛卡尔乘积，然后离开它连接到其他

Answer 2

使用此：

SELECT * 
FROM Table1 
LEFT OUTER JOIN Table2 ON Table1.PersonID = Table2.PersonID 
LEFT OUTER JOIN Table3 ON Table1.PersonID = Table3.PersonID 
LEFT OUTER JOIN Table4 ON Table1.PersonID = Table4.PersonID 
LEFT OUTER JOIN Table5 ON Table1.PersonID = Table5.PersonID 
LEFT OUTER JOIN Table6 ON Table1.PersonID = Table6.PersonID 

看那SQL Joins形式的更多信息。