如何使用codeigniter查询获取列的总和 [英] how to get sum of a column with codeigniter query

问题描述

我正在尝试使用codeigniter查询获取mysql表中列值的总和

I am trying to get sum of a column values in mysql table with the codeigniter query as

$this->db
     ->query("Select SUM(tb1.amount) from table1 tb1 inner join table2 tb2 on tb2.Id=tb1.Id Where tb2.Status='1'")
     ->result()

它给我一个错误，因为数组到字符串转换我只需要一个数字，例如 count(amount)返回带有num_row()的行数

it give me error as array to string conversion I need just a number such count(amount) returns number of rows with num_row()

推荐答案

用作=> $ data ['total']

$data = $this->db
     ->query("Select SUM(tb1.amount) as total from table1 tb1 inner join table2 tb2 on tb2.Id=tb1.Id Where tb2.Status='1'")
     ->row_array()

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