Question

我有一个嵌套的SQL查询，如下所示。

SELECT  A.ID, A.fName, A.lName,
   COALESCE (B.calls, 0) AS Calls
FROM TableA AS  A
   LEFT JOIN
   (
      SELECT COUNT(B.event) AS  Calls, B.ID
      FROM TableB AS B
      WHERE B.event LIKE 'call'
        AND `Time` >= 1360540800
        AND `Time` <= 1361232000
      GROUP BY B.ID

    ) B
      ON A.ID = B.ID 
WHERE A.State  LIKE 'SENT' OR A.State  LIKE 'SET'

我正在尝试以codeigniter样式转换它。我知道Code Igniter的Active Record类本身不支持子查询。但是怎么可能这样做呢。我一直在尝试下面的代码。所以我做了两个不同的查询，并使用union进行组合，如下所示：

$query  = $this->db->query("select * from $subQuery2 UNION $subQuery1  as unionTable ");

Union不是正确的方法，可以帮助我将其转换为codeigniter风格。

Answer 1

您可以使用codeigniter的子查询方式为此目的执行此操作，您将不得不破解codeigniter。像这样转到system / database / DB_active_rec.php从这些函数中删除public或protected关键字

public function _compile_select($select_override = FALSE)
public function _reset_select()

现在子查询写入可用现在这里是带有活动记录的查询

$data   =   array(
                'COUNT(B.event) AS  Calls',
                'B.ID'
            );

$this->db
        ->select($data)
        ->from('TableB AS B')
        ->like('B.event','call','both')
        ->where('`Time` >=',1360540800)
        ->where('`Time` <=',1361232000)
        ->group_by('B.ID');

$subQuery = $this->db->_compile_select();
$this->db->_reset_select();
unset($data);
$data   =   array(
                'A.ID',
                'A.fName',
                'A.lName',
                'COALESCE (B.calls, 0) AS Calls'
            );
$this->db
        ->select($data)
        ->from('TableA AS A')
        ->join("$subquery")
        ->like('A.State','SENT','both')
        ->or_like('A.State','SET','both');

我已根据您的要求将两者都放在您可以做的事情中。注意：使用子查询时，必须使用

$this->db->from('myTable')

而不是

$this->db->get('myTable')

运行查询。

将嵌套mysql查询转换为codeigniter样式

1 个答案: