0

I have an SQL statement, that selets sport classes/courses (courses) with their trainers (trainers) over an association table (courses_trainers). Since some courses have multiple trainers, I use the GROUP_CONCAT(...) function to get the trainer names into one field. Some trainers rows are empty or NULL, so I add a trainers.name IS NOT NULL and a trainers.name != "" condition to the ON clause of the trainers JOIN:

SQL statement

SELECT
    courses.id AS id,
    GROUP_CONCAT(DISTINCT trainers.name SEPARATOR "|||") AS trainers
    ...
FROM
    courses
    ...
LEFT JOIN
    courses_trainers ON courses.id = courses_trainers.course_id
LEFT JOIN
    trainers ON trainer_id = trainers.id
    AND trainers.name IS NOT NULL
    AND trainers.name != ""
    ...
...
WHERE `courses`.`id` = '898'
GROUP BY
    courses.id
;

OO variant in the CourseTable class

public function findOnceByID($id) { 
    $concatDelimiter = self::CONCAT_DELIMITER;
    $select = new Select();
    ...
    $select->columns(array(
        'id', ...
    ));
    $select->from($this->tableGateway->getTable());
    $select
        ...
        ->join('courses_trainers', 'courses.id = courses_trainers.course_id', array(), Select::JOIN_LEFT)
        ->join('trainers', 'trainer_id = trainers.id AND trainers.name IS NOT NULL AND trainers.name != ""', array(
            'trainers' => new Expression('GROUP_CONCAT(DISTINCT trainers.name SEPARATOR "' . $concatDelimiter . '")')
            ), Select::JOIN_LEFT)
        ...
    ;
    $where
        ->equalTo('courses.id', $id)
    ;
    $select->where($where, Predicate::OP_AND);
    $select->group('courses.id');
    $resultSet = $this->tableGateway->selectWith($select);
    return $resultSet;
}

The generated JOIN code I get looks like this:

LEFT JOIN
    `courses_trainers` ON `courses`.`id` = `courses_trainers`.`course_id`
LEFT JOIN
    `trainers` ON `trainer_id` = `trainers`.`id`
    AND `trainers`.`name` `IS` `NOT` `NULL`
    AND `trainers`.`name` `!`= `"``"`

So, here is to much quoted.

How to "explain" to the ZF, that IS, NOT, " etc. should not be quoted?

4

2 回答 2

0

该join方法接受一个表达式作为ON子句的第二个参数

->join('trainers', new Expression('trainer_id = trainers.id AND trainers.name IS NOT NULL AND trainers.name != ""'),
于 2013-04-17T13:58:11.583 回答
0

负责引用的是Zend\Db\Adapter\Platform\PlatformInterface#quoteIdentifierInFragment(...)（或更准确地说是它的实现，在这种情况下是 in Zend\Db\Adapter\Platform\Mysql），它作为第二个参数获得一个“安全词”数组。Zend\Db\Sql\Select#processJoins(...) 传递给它array('=', 'AND', 'OR', '(', ')', 'BETWEEN', '<', '>')。因为IS,NOT等!不在列表中，所以它们被引用。

解决方案是扩展Zend\Db\Sql\Select并覆盖其processJoins(...)，将所需的额外“安全词”添加到quoteIdentifierInFragment(...)调用中第二个参数的列表中：

<?php
namespace MyNamespace\Db\Sql;

use Zend\Db\Adapter\Driver\DriverInterface;
use Zend\Db\Adapter\StatementContainerInterface;
use Zend\Db\Adapter\ParameterContainer;
use Zend\Db\Adapter\Platform\PlatformInterface;
use Zend\Db\Sql\Select as ZendSelect;

class Select extends ZendSelect
{

    ...

    protected function processJoins(PlatformInterface $platform, DriverInterface $driver = null, ParameterContainer $parameterContainer = null)
    {
        ...
        // process joins
        $joinSpecArgArray = array();
        foreach ($this->joins as $j => $join) {
            ...
            $joinSpecArgArray[$j][] = ($join['on'] instanceof ExpressionInterface)
                ? $this->processExpression($join['on'], $platform, $driver, $this->processInfo['paramPrefix'] . 'join' . ($j+1) . 'part')
                : $platform->quoteIdentifierInFragment($join['on'], array('=', 'AND', 'OR', '(', ')', 'BETWEEN', '<', '>', '!', 'IS', 'NULL', 'NOT', '"')); // on
            ...
        }

        return array($joinSpecArgArray);
    }

    ...

}
于 2013-04-17T12:57:10.913 回答