php - 如何使用 codeigniter 查询获取列的总和

Question

我正在尝试使用 codeigniter 查询获取 mysql 表中列值的总和

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

它给我的错误为 array to string conversion我只需要一个这样的数字 count(amount) returns number of rows with num_row()

Answer 1

您可以使用codeigniter的select_sum()函数。尝试以下代码-

$query = $this->db->select_sum("tb1.amount")
                  ->from("table1 as tb1")
                  ->join("table2 as tb2","tb1.id = tb2.id") 
                  ->where("tb2.status",1)
                  ->get();
$query = $query->result();

或

$query = $this->db->query('SELECT sum(tb1.amount) FROM table1 as tb1 join table2 as tb2 on tb1.id = tb2.id where tb1.status = 1') ; $query = $query->result_array();