SQL left join twice from one table web2py

How to do this thing? I have two table

Table1:

-id
-table2_id_1
-table2_id_2

Table2:

-id
-table3_id

Table3:

-id 
-table4_id
-table5_id
-table6_id

Table4, Table5 and Table6:

-id
-name
-date

Main table is Table1

db(db.Table1).select()

I need to join twice Table2(colums) in witch i need to join Table3(in each table2_id_1 and table2_id_2 field table3_id is equals), than join Table4,Table5,Table6

---

我不知道，如果我真的得到了你想要做的事情，但是如果你只是想根据id来加入表格，那么应该这样做：

SELECT *
FROM table1 a JOIN table2 b ON (a.table2_id_1 = b.id) JOIN
     table2 c ON (a.table2_id_2 = c.id) JOIN
     table3 d ON (b.table3_id = d.id) JOIN
     table3 e ON (c.table3_id = e.id) JOIN
     table4 f ON (d.table4_id = f.id) JOIN 
     table5 g ON (d.table5_id = g.id) JOIN
     table6 h ON (d.table6_id = h.id) JOIN
     table4 i ON (e.table4_id = i.id) JOIN 
     table5 j ON (e.table5_id = j.id) JOIN
     table6 k ON (e.table6_id = k.id)

链接地址: http://www.djcxy.com/p/94300.html

上一篇: 使用php mysql从五个表中选择

下一篇: SQL从一个表web2py中左连接两次