学说 ORM 中的 Substring_index 函数

问题描述

我必须在 symfony 2 的学说 ORM 中使用 SUBSTRING_INDEX 函数.我该怎么做?现在在查询中使用它会给我未定义的函数错误:

I have to use SUBSTRING_INDEX function in doctrine ORM in symfony 2. How can I do this? Right now using it inside the query gives me undefined function error:

[Syntax Error] line 0, col 299: Error: Expected known function, got 'SUBSTRING_INDEX'

我使用这个函数来获取第一个数字，例如:

I use this function to get the first number from, for example:

11.48.205.1

我该如何解决这个问题?

How can I solve this?

推荐答案

这里是代表 SUBSTRING_INDEX 函数的类(不要忘记更新命名空间).

Here is class that represent SUBSTRING_INDEX function (don't forget to update namespace).

<?php

namespace SadFunctions;

use DoctrineORMQueryASTFunctionsFunctionNode;
use DoctrineORMQueryLexer;
use DoctrineORMQuerySqlWalker;
use DoctrineORMQueryParser;

/**
 * "SUBSTRING_INDEX" "(" ArithmeticPrimary "," ArithmeticPrimary "," ArithmeticPrimary ")"
 *
 * @author  Andrey Stepanov <stepashka@gmail.com>
 */
class SubstringIndexFunction extends FunctionNode
{
    public $str = null;
    public $delim = null;
    public $count = null;

    /**
     * @override
     */
    public function getSql(SqlWalker $sqlWalker)
    {
        return 'SUBSTRING_INDEX(' .
            $this->str->dispatch($sqlWalker) . ', ' .
            $this->delim->dispatch($sqlWalker) . ', ' .
            $this->count->dispatch($sqlWalker) .
        ')';
    }

    /**
     * @override
     */
    public function parse(Parser $parser)
    {
        $parser->match(Lexer::T_IDENTIFIER);
        $parser->match(Lexer::T_OPEN_PARENTHESIS);
        $this->str = $parser->ArithmeticPrimary();
        $parser->match(Lexer::T_COMMA);
        $this->delim = $parser->ArithmeticPrimary();
        $parser->match(Lexer::T_COMMA);
        $this->count = $parser->ArithmeticPrimary();
        $parser->match(Lexer::T_CLOSE_PARENTHESIS);
    }
}

在创建实体管理器之前需要先注册:

You need to register it before creating entity manager:

$config->addCustomStringFunction('SUBSTRING_INDEX', 'SadFunctionsSubstringIndexFunction');
/* ... */
$entityManager = EntityManager::create($conn, $config);

完成后，您将获得以下结果:

After you do it you'll get the following results:

echo $entityManager->createQuery("SELECT p FROM SadSchemaAbstractPageAny as p WHERE SUBSTRING_INDEX(p.name,'a',1) = 'P'")->getSQL();
// Output: SELECT p0_.id AS id_0, p0_.name AS name_1, p0_.type AS type_2 FROM page p0_ WHERE (SUBSTRING_INDEX(p0_.name, 'a', 1) = 'P')

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