将MySQL转换为Doctrine查询生成器。 IF和CONCAT的问题。或者另一种方法来选择子查询 [英] Converting MySQL to Doctrine Query Builder. Issues with IF and CONCAT. Or another approach for subqueries on select

问题描述

我有一个表格，我的类别，每个类别有和id，名称和parent_id。

I have a table for my categories, each category have and id, name and parent_id.

Select IF(a.parent_id IS NULL, a.name, CONCAT((SELECT b.name FROM category b WHERE b.id = a.parent_id), " / ", a.name) ) as n, a.id, a.parent_id
FROM category a
ORDER BY n

我想将其转换为我的Doctrine2查询生成器

I want to convert it to my Doctrine2 Query Builder

    $em = $this->getDoctrine()->getEntityManager();
    $qb = $em->createQueryBuilder();
    $q = $qb
            ->select("c.id")
            ->addSelect(
                "IF(c.parent_id IS NULL, c.name, CONCAT((" .
                $em->createQueryBuilder()
                   ->select("t.name")
                   ->from("MyBundle:Category", "t")
                   ->getQuery()->getDQL() .
                "), \" / \", c.name) )"
            )
            ->from("MyBundle:Category", "c");
    echo $q->getQuery()->getSQL();
    exit;

这样的东西，但是我不能使用 IF 和 CONCAT 。

Something like that, but I cant use the IF, and CONCAT.

推荐答案

确定我找到了解决方案。

Ok I found the solution.

您可以使用 CASE 而不是 IF 。检查这个，但是当我使用 CASE 我不能 CONCAT 我的字段：

You can use CASE instead of IF. Check this out, but when I am using CASE I can't CONCAT my fields:

$em = $this->getDoctrine()->getEntityManager();
$qb = $em->createQueryBuilder();
$q = $qb
      ->select("c.id")
      ->addSelect("CASE WHEN (c.parent IS NULL) THEN c.name ELSE 'something' END")
      ->from("MyBundle:Category", "c")
      ->leftJoin("c.parent", "t");

echo $q->getQuery()->getSQL();

另一个解决方案是创建自己的DQL函数，如 IF 并使用它：

Another Solution is create your own DQL function, like IF and use it like this:

$em = $this->getDoctrine()->getEntityManager();
$qb = $em->createQueryBuilder();
$q = $qb
      ->select("c.id")
      ->addSelect("IF(c.parent IS NULL, c.name, CONCAT(CONCAT(t.name, ' / '), c.name))")
      ->from("MyBundle:Category", "c")
      ->leftJoin("c.parent", "t");

echo $q->getQuery()->getSQL();

要创建此IF，您可以访问此链接并学习： http://docs.doctrine-project.org/projects/doctrine-orm/en/latest/reference/dql-doctrine-query-language.html#adding-your-own-functions-to-the-dql -l语言

For create this IF you can go to this link and learn: http://docs.doctrine-project.org/projects/doctrine-orm/en/latest/reference/dql-doctrine-query-language.html#adding-your-own-functions-to-the-dql-language

我将在这里发布这个IF的类和config.yml来帮助别人。
这是IfFunction类（我从 https://github.com/beberlei/DoctrineExtensions/blob/master/src/Query/Mysql/IfElse.php ）：

I will post here my class for this IF and the config.yml to help other people. Here is the IfFunction class (I got that from https://github.com/beberlei/DoctrineExtensions/blob/master/src/Query/Mysql/IfElse.php):

<?php
namespace MyName\MiscBundle\Doctrine\ORM\Query\AST\Functions;

use Doctrine\ORM\Query\AST\Functions\FunctionNode;
use Doctrine\ORM\Query\Lexer;

/**
 * Usage: IF(expr1, expr2, expr3)
 * 
 * If expr1 is TRUE (expr1 <> 0 and expr1 <> NULL) then IF() returns expr2;
 * otherwise it returns expr3. IF() returns a numeric or string value,
 * depending on the context in which it is used. 
 * 
 * @author  Andrew Mackrodt <[e-mail]>
 * @version 2011.06.19
 */
class IfFunction extends FunctionNode
{
    private $expr = array();

    public function parse(\Doctrine\ORM\Query\Parser $parser)
    {
        $parser->match(Lexer::T_IDENTIFIER);
        $parser->match(Lexer::T_OPEN_PARENTHESIS);
        $this->expr[] = $parser->ConditionalExpression();

        for ($i = 0; $i < 2; $i++)
        {
            $parser->match(Lexer::T_COMMA);
            $this->expr[] = $parser->ArithmeticExpression();
        }

        $parser->match(Lexer::T_CLOSE_PARENTHESIS);
    }

    public function getSql(\Doctrine\ORM\Query\SqlWalker $sqlWalker)
    {
        return sprintf('IF(%s, %s, %s)',
            $sqlWalker->walkConditionalExpression($this->expr[0]),
            $sqlWalker->walkArithmeticPrimary($this->expr[1]),
            $sqlWalker->walkArithmeticPrimary($this->expr[2]));
    }
}

之后，您需要更新您的config.yml，这个（刚添加最后3行）：

After that you need to update your config.yml like this (just added the last 3 lines):

doctrine:
    dbal:
        driver:   "%database_driver%"
        host:     "%database_host%"
        port:     "%database_port%"
        dbname:   "%database_name%"
        user:     "%database_user%"
        password: "%database_password%"
        charset:  UTF8

    orm:
        auto_generate_proxy_classes: "%kernel.debug%"
        auto_mapping: true
        dql: #ADDED THIS LINE
            string_functions: #ADDED THIS LINE
                IF: MyName\MiscBundle\Doctrine\ORM\Query\AST\Functions\IfFunction #ADDED THIS LINE

谢谢

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