INNER JOIN使用Doctrine QueryBuilder从Select Statement获得结果

Question

您可以使用Doctrine QueryBuilder来INNER JOIN来自包含SELECT的完整GROUP BY语句的临时表吗？

最终目标是选择最佳版本的唱片。我有一个viewVersion表，有多个版本具有相同的viewId值但不同的timeMod。我想找到具有最新timeMod的版本（并在查询上执行许多其他复杂的连接和过滤）。

最初人们假设您可以执行GROUP BY viewId然后ORDER BY timeMod，但ORDER BY对GROUP BY没有影响，MySQL会返回随机结果。有很多答案（例如here）解释了使用GROUP并提供解决方案的问题，但我在解释Doctrine文档时找不到使用Doctrine QueryBuilder实现SQL的方法（如果它甚至可能）。为什么我不使用DQL？我可能不得不这样做，但我有很多动态过滤器和连接，使用QueryBuilder更容易，所以我想看看是否可能。

在Doctrine QueryBuilder中重现MySQL的样本

SELECT vv.* 
FROM view_version vv
#inner join only returns where the result sets overlap, i.e. one record
INNER JOIN (
    SELECT MAX(timeMod) maxTimeMod, viewId
    FROM view_version
    GROUP BY viewId
) version ON version.viewId = vv.viewId AND vv.timeMod = version.maxTimeMod
#join other tables for filter, etc
INNER JOIN view v ON v.id = vv.viewId
INNER JOIN content_type c ON c.id = v.contentTypeId
WHERE vv.siteId=1
AND v.contentTypeId IN (2)
ORDER BY vv.title ASC;

通过查询生成器的理论解决方案（不工作）

我认为JOIN需要注入一个DQL语句，例如

$em = $this->getDoctrine()->getManager();
$viewVersionRepo = $em->getRepository('GutensiteCmsBundle:View\ViewVersion');

$queryMax = $viewVersionRepo->createQueryBuilder()
    ->addSelect('MAX(timeMod) AS timeModMax')
    ->addSelect('viewId')
    ->groupBy('viewId');

$queryBuilder = $viewVersionRepo->createQueryBuilder('vv')
    // I tried putting the query in a parenthesis, to no avail
    ->join('('.$queryMax->getDQL().')', 'version', 'WITH', 'vv.viewId = version.viewId AND vv.timeMod = version.timeModMax')
    // Join other Entities
    ->join('e.view', 'view')
    ->addSelect('view')
    ->join('view.contentType', 'contentType')
    ->addSelect('contentType')
    // Perform random filters
    ->andWhere('vv.siteId = :siteId')->setParameter('siteId', 1)
    ->andWhere('view.contentTypeId IN(:contentTypeId)')->setParameter('contentTypeId', $contentTypeIds)
    ->addOrderBy('e.title', 'ASC');

$query = $queryBuilder->getQuery();
$results = $query->getResult();

我的代码（可能与上述示例完全不符）输出：

SELECT e, view, contentType 
FROM Gutensite\CmsBundle\Entity\View\ViewVersion e 
INNER JOIN (
    SELECT MAX(v.timeMod) AS timeModMax, v.viewId 
    FROM Gutensite\CmsBundle\Entity\View\ViewVersion v 
    GROUP BY v.viewId
) version WITH vv.viewId = version.viewId AND vv.timeMod = version.timeModMax 
INNER JOIN e.view view 
INNER JOIN view.contentType contentType 
WHERE e.siteId = :siteId 
AND view.contentTypeId IN (:contentTypeId) 
ORDER BY e.title ASC

This Answer似乎表明它可能在IN语句之类的其他上下文中，但是当我在JOIN中尝试上述方法时，我收到错误：

[Semantical Error] line 0, col 90 near '(SELECT MAX(v.timeMod)': Error: Class '(' is not defined.

Answer 1

非常感谢@AdrienCarniero为他的alternative query structure用最简单的JOIN排序最高版本，其中实体的timeMod小于连接的表timeMod。

替代查询

SELECT view_version.* 
FROM view_version
#inner join to get the best version
LEFT JOIN view_version AS best_version ON best_version.viewId = view_version.viewId AND best_version.timeMod > view_version.timeMod
#join other tables for filter, etc
INNER JOIN view ON view.id = view_version.viewId
INNER JOIN content_type ON content_type.id = view.contentTypeId
WHERE view_version.siteId=1
# LIMIT Best Version
AND best_version.timeMod IS NULL
AND view.contentTypeId IN (2)
ORDER BY view_version.title ASC;

使用Doctrine QueryBuilder

$em = $this->getDoctrine()->getManager();
$viewVersionRepo = $em->getRepository('GutensiteCmsBundle:View\ViewVersion');

$queryBuilder = $viewVersionRepo->createQueryBuilder('vv')
    // Join Best Version
    ->leftJoin('GutensiteCmsBundle:View\ViewVersion', 'bestVersion', 'WITH', 'bestVersion.viewId = e.viewId AND bestVersion.timeMod > e.timeMod')
    // Join other Entities
    ->join('e.view', 'view')
    ->addSelect('view')
    ->join('view.contentType', 'contentType')
    ->addSelect('contentType')
    // Perform random filters
    ->andWhere('vv.siteId = :siteId')->setParameter('siteId', 1)
    // LIMIT Joined Best Version
    ->andWhere('bestVersion.timeMod IS NULL')
    ->andWhere('view.contentTypeId IN(:contentTypeId)')->setParameter('contentTypeId', $contentTypeIds)
    ->addOrderBy('e.title', 'ASC');

$query = $queryBuilder->getQuery();
$results = $query->getResult();

就性能而言，它实际上取决于数据集。 See this discussion for details。

提示：该表应包含这两个值（viewId和timeMod）的索引，以加快结果。我不知道它是否也会从两个字段的单个索引中受益。

使用原始JOIN方法的本机SQL查询在某些情况下可能更好，但是在动态创建它的扩展代码范围内编译查询，并且使映射正确是一种痛苦。所以这至少是一种替代解决方案，我希望能帮助其他人。