如何使用Codeigniter互连三个mysql表

问题描述

我有以下三个表。我试图在这三个表之间互相链接（加入），像这样 -

链接1

  table1.code = table2.account-code 
 table1.code = table3.t-code 
 table2.voucher_no = table3.voucher_no 
  

我试图以Codeignitier的方式查询，但我收到一条错误消息，表明table1不是唯一的或类似的。

这里是我尝试的（并得到错误）

  $ this-> db-> select '）; 
 $ this-> db-> from（'table2'）; 
 $ this-> db-> join（'table3'，'table2.voucher_no = table3.voucher_no'）; 
 $ this-> db-> join（'table1'，'（table1.code = table2.account_code）'）; 
 $ it-> db-> join（'table1'，'（table1.code = table3.t_code）'）; 
  

请告诉我我做错了什么？

解决方案

  $ this-> db-> select（'table1。*，table2。*，table3。*'）; 
 $ this-> db-> from（'table2'）; 
 $ this-> db-> join（'table3'，'table2.voucher_no = table3.voucher_no'，'left'）; 
 $ this-> db-> join（'table1'，'table1.code = table2.account_code AND table1.code = table3.t_code'，'left'）; 
 $ this-> db-> get（）; 
  

如果你想选择所有三个表c我选择statment
还看看join如何

这将产生此查询

  SQL：SELECT`table1`。*，`table2`。*，`table3`。* FROM（`table2`）LEFT JOIN`table3 `ON`table2`.`voucher_no` =`table3`.`voucher_no` LEFT JOIN`table1` ON`table1`.`code` =`table2`.`account_code`和table1.code = table3.t_code 
  

并用于测试目的

I have the following three tables. I am trying to inter link (join) among these three tables like this-

link 1

table1.code=table2.account-code
table1.code=table3.t-code
table2.voucher_no=table3.voucher_no

I tried to query in Codeignitier's way but I get an error message that says table1 is not unique or something like that.

here's what I tried(and got the error)

  $this->db->select('*');
   $this->db->from('table2');
   $this->db->join('table3', 'table2.voucher_no = table3.voucher_no');
  $this->db->join('table1', '(table1.code = table2.account_code)');
  $this->db->join('table1', '(table1.code = table3.t_code)');

Would you please kindly show me where I did wrong?

解决方案

$this->db->select('table1.* , table2.* , table3.*');
$this->db->from('table2');
$this->db->join('table3', 'table2.voucher_no = table3.voucher_no','left');
$this->db->join('table1', 'table1.code = table2.account_code AND table1.code = table3.t_code','left');
$this->db->get();

If you want to select all three table c my select statmentALso see how join are used i have removed brackets you used in joins.

EDITED

This will produce this query

SQL: SELECT `table1`.*, `table2`.*, `table3`.* FROM (`table2`) LEFT JOIN `table3` ON `table2`.`voucher_no` = `table3`.`voucher_no` LEFT JOIN `table1` ON `table1`.`code` = `table2`.`account_code` AND table1.code = table3.t_code

And for testing purpose

http://brettdewoody.com/labs/active-check/index.php

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