zend framework2 - ZF2/PHP - 如何从查询中提取标量记录并用作第二个查询的 where 子句的参

信息

我有一个应用程序，我想在其中查询一个表，以便能够获取具有最小 id 的记录。 为了简化我的理解，我在两个表方法中编写了两个查询。

我能够使用硬编码标量查询数据库，但无法根据来自另一个查询的查询标量进行查询。

问题

如何从 Zend Framework 2 中的查询中提取标量值，并将该值用作另一个（主）查询的 where 子句的输入？

法典

   public function getMinActionItemID()
    {
        $select = new Select();
        $select->from('actionitems', array('MinActionItemID'))->columns(array('MinActionItemID' => new Expression('min(ActionItemID)')));
        $resultSet = $this->tableGateway->selectWith($select);
        $resultSet->buffer();
        return $resultSet;
    }
public function getFirstActionItem()
{       
    var_dump($this->getMinActionItemID());
    $select = new Select();
    $select->from('actionitems')->where(array('ActionItemID' => $this->getMinActionItemID()));
    $row = $this->tableGateway->selectWith($select);        
    if (!$row) {
        throw new Exception("Action Item Not Found");
    }
    return $row;
}

我能够从查询中获取以下内容，但无法从下面的对象中获取标量值，该对象从getFirstActionItemID()返回并传递到 getFirstActionItem() 方法的 where 子句中。

  object(Zend'Db'ResultSet'ResultSet)[288]
  protected 'count' => int 1
  protected 'dataSource' => 
    object(Zend'Db'Adapter'Driver'Pdo'Result)[266]
      protected 'statementMode' => string 'forward' (length=7)
      protected 'fetchMode' => int 2
      protected 'resource' => 
        object(PDOStatement)[267]
          public 'queryString' => string 'SELECT min(ActionItemID) AS `MinActionItemID` FROM `actionitems`' (length=64)
      protected 'options' => null
      protected 'currentComplete' => boolean true
      protected 'currentData' => 
        array (size=1)
          'MinActionItemID' => string '1' (length=1)
      protected 'position' => int 0
      protected 'generatedValue' => string '0' (length=1)
      protected 'rowCount' => int 1
  protected 'fieldCount' => int 1
  protected 'position' => int 0

编辑

我

最终放弃了我的方法，并使用了提供的答案。 我还保留了getMinActionItemID()，以便在导航到第一个和最后一个记录并尝试在我的应用程序中转到下一个或上一个记录时使用它进行边界检查。

通过智能感知的一些调查，我终于找到了一种方法来获得所需的标量。事后看来，我找到了答案和这段代码来解决我的导航问题（一次一条记录）。

如何从查询中获取标量

答

use Zend'Db'Adapter'Driver'Pdo'Result;
/* @var $resultSet ResultSet */
    /* @var $dataSource Result */
    public function getMinActionItemID()
    {
        $select = new Select();
        $select->from('actionitems', array('MinActionItemID'))->columns(array('MinActionItemID' => new Expression('min(ActionItemID)')));
        $resultSet = $this->tableGateway->selectWith($select);
        $dataSource = $resultSet->getDataSource();
        return $dataSource->getResource()->fetchAll()[0]['MinActionItemID'];
    }

用法

public function getNextActionItem($id)
{
    if ($id == $this->getMaxActionItemID())
    {
        return $this->getActionItem($id);
    }
    $select = new Select();
    $select->from('actionitems')
           ->where("ActionItemID > $id")
           ->order('ActionItemID')
           ->limit(1);
    $row = $this->tableGateway->selectWith($select);
    if (!$row) {
        throw new Exception ("Action Item Not Found");
    }
    return $row;
}

    use Zend'Db'Sql'Expression;
    use Zend'Db'Sql'Select;
    ...
    $set   = $table->select( function( Select $s ){
        $sub = new Select('actionitems');
        $sub->columns( [ 'min_id' => new Expression( 'MIN(ActionItemID)') ] );
        $s->columns(['*'])
            ->where([ 'ActionItemID' => $sub ])
                ->limit( 1 );
    });
    var_dump( $set->current() );

public function getFirstActionItem()
{
    $select = $this->tableGateway->getSql()->select();
    $select->order('ActionItemID');
    $select->limit(1);
    $row = $this->tableGateway->selectWith($select)->current();
    if (!$row) {
        throw new Exception('Action Item Not Found');
    }
    return $row;
}

 $dataSource = $resultSet->getDataSource();
 $minActionItemID =  $dataSource->getResource()->fetchAll()[0]['MinActionItemID'];  //Note: [0] is the first record and ['MinActionItemID'] is the field name of the custom query