Question

我是codeigniter的初学者我有这样的查询，我想在codeigniter中使用此查询

SELECT sum(price) 
FROM (SELECT price
      FROM items
      ORDER BY price DESC
      LIMIT 3
) AS subquery;

我做过

$this->db->select('SUM(price)');
$this->db->select('price');
$this->db->from('items');
$this->db->order_by('price desc');
$this->db->limit(3);
$this->db->get();

这会产生这样的输出

SELECT sum(price), price
      FROM items
      ORDER BY price DESC
      LIMIT 3;

我该怎么办？

Answer 1

像这样使用

$this->db->select_sum('price');
$this->db->select('price');
$this->db->from('items');
$this->db->order_by('price desc');
$this->db->limit(3);
$this->db->get();

Answer 2

如果您的查询工作正常，请将其简化。

$query = $this->db->query('SELECT sum(price) FROM (SELECT price FROM items ORDER BY price DESC LIMIT 3 ) AS subquery');
print_r($query->result_array());

Answer 3

您可以使用这样的查询

$this->db->select_sum('price');
$this->db->from('items');
$this->db->order_by('price desc');
$this->db->limit(3);
$this->db->get();

如果要将数据放入数组，则：

 $data=$this->db
    ->select_sum('price')
    ->from('items')
     ->order_by('price desc')
    ->limit(3)
    ->get();
return $data->result_array();

Answer 4

 public function advanceSalary($id) {
        if ($id) {
            $this->db->select('salaryLaser.*');
            //$this->db->select_sum('salaryLaser.credit');
            $this->db->select('SUM(salaryLaser.credit) as creditTotal');
            $this->db->select('SUM(salaryLaser.debit) as debitTotal');
            $this->db->from($this->salaryLaser);
            $this->db->where('salaryLaser.employeeId', $id);
            $this->db->where('salaryLaser.employeeRole', '1');
            $advance = $this->db->get();
            if ($advance->num_rows() > 0) {
                return $advance->row();
            } else {
                return FALSE;
            }
        } else {
            return FALSE;
        }
    }

Answer 5

尝试此操作来修复它：

 /**
  * [total_currency description]
  * @param  [type] $column_name [description]
  * @param  [type] $where       [description]
  * @param  [type] $table_name  [description]
  * @return [type]              [description]
  */

function total_count($column_name,  $where, $table_name)
{
   $this->db2->select_sum($column_name);
    // If Where is not NULL
    if(!empty($where) && count($where) > 0 )
    {
       $this->db2->where($where);
    }

      $this->db2->from($table_name);
        // Return Count Column
return $this->db2->get()->row($column_name);//table_name array sub 0




 }

从Codeigniter中的Result with Limit中选择SUM

5 个答案: