[英]ZF - MySQL SUM query using CASE WHEN
尝试在zend框架中编写以下查询1:
SELECT
SUM(CASE WHEN column2 = 'value1' THEN column3 END) AS 'mySpecialSum',
FROM `my_table`
WHERE column4='value2' AND column5='value3'
测试我正在这样写:
$select = $this->select()
->from('my_table', array(
'mySpecialSum'=>'SUM(CASE WHEN column2 = "value1" THEN column3 END)'
))
->where('column4=?', $value2)
->where('column5=?', $value3);
$data = $this->fetchAll($select);
哪个有效-但我需要知道如何将value1
作为变量包括-例如$value1
最好使用占位符,以便语句“准备好”-以最大程度减少SQL注入的机会。
当前正在尝试两个选项(不起作用):
$select = $this->select()
->from('my_table', array(
'mySpecialSum'=>'SUM(CASE WHEN column2 = "{$value1}" THEN column3 END)'
))
->where('column4=?', $value2)
->where('column5=?', $value3);
$data = $this->fetchAll($select);
要么
$select = $this->select()
->from('my_table', array(
'mySpecialSum'=>'SUM(CASE WHEN column2 = "{$this->_db->quote($value1)}" THEN column3 END)'
))
->where('column4=?', $value2)
->where('column5=?', $value3);
$data = $this->fetchAll($select);
在这里对准备好的语句进行了一些研究之后,看来最好的方法是:
$sql = 'SELECT SUM(CASE WHEN column2 = ? THEN column3 END) AS "mySpecialSum",
FROM my_table
WHERE content_type = ?
AND content_id = ?';
$preparedStatement = $this->getAdapter()->query($sql, array($value1, $value2, $value3));
$data = $preparedStatement->fetchAll();
两个选项也都可以使用 -但都感觉像是被黑客入侵(顺便说一下,它们也比上面的“ prepared statement”方法要慢一些)-
$select = $this->select()
->from('my_table', array(
'mySpecialSum'=>'SUM(CASE WHEN column2 = "' . $value1 . '" THEN column3 END)'
))
->where('column4=?', $value2)
->where('column5=?', $value3);
$data = $this->fetchAll($select);
和:
$start = microtime();
$select = $this->select()
->from('my_table', array(
'mySpecialSum'=>'SUM(CASE WHEN column2 = ' . $this->_db->quote($value1) . ' THEN column3 END)'
))
->where('column4=?', $value2)
->where('column5=?', $value3);
$data = $this->fetchAll($select);
$end = microtime();
$timeTaken = $end - $start;
之前和之后的microtime()
是一项速度测试,用于比较两种方法:
...显示使用zf $this->_db->quote()
差异可忽略不计
但是,奇怪的是,使用$this->getAdapter()->select()
而不是简单地使用$this->select()
时,速度提高了5倍:
$select = $this->getAdapter()
->select()
->from('my_table', array(
'mySpecialSum'=>'SUM(CASE WHEN column2 = ' . $this->_db->quote($value1) . ' THEN column3 END)'
))
->where('column4=?', $value2)
->where('column5=?', $value3);
$data = $this->getAdapter()->fetchAll($select);
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