codeigniter中的Mysql查询求和查询

Question

Split mysql column in codeigniter

上面的链接是我的问题之一。我得到了上述问题的答案。但是现在我有一个sql查询如下，

SELECT SUM(IF(pay_type = 1, `pay_amount`, `0))` mess_pay, SUM(IF(pay_type=2, `pay_amount`, `0))` est_pay FROM (`mess_stock`);

我想在 codeigniter 中使用上面的代码。

下面的方法我试过了

$this->db->select('SUM(IF(pay_type = 1, pay_amount, 0)) mess_pay, SUM(IF(pay_type=2, pay_amount, 0)) est_pay');
$this->db->from('mess_stock');

但它抛出以下输出

A Database Error Occurred
Error Number: 1064
You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'mess_pay, SUM(IF(pay_type=2, `pay_amount`, `0))` est_pay FROM (`mess_stock`)' at line 1


SELECT SUM(IF(pay_type = 1, `pay_amount`, `0))` mess_pay, SUM(IF(pay_type=2, `pay_amount`, `0))` est_pay FROM (`mess_stock`)


Filename: /var/www/college/modules/mess_fees/models/mess_fees_model.php
Line Number: 25

如何执行上述查询？

Answer 1

将 select() 的最后一个参数设置为 false :

$this->db->select('SUM(IF(pay_type = 1, pay_amount, 0)) mess_pay, SUM(IF(pay_type=2, pay_amount, 0)) est_pay', false);

它将阻止 CI 添加 ``。

看看文档:http://www.codeigniter.com/user_guide/database/active_record.html#select

$this->db->select() accepts an optional second parameter. If you set it to FALSE, CodeIgniter will not try to protect your field or table names with backticks. This is useful if you need a compound select statement.