如何在 laravel 中执行复杂的 mysql 查询

Question

我有一个下面的 mysql 查询，它工作正常，但我想使用准备语句运行它。

SET @sql = NULL;

SELECT GROUP_CONCAT(CONCAT("SELECT '",colname,":' AS 'Label',GROUP_CONCAT(JSON_UNQUOTE(JSON_EXTRACT(attr_details,'$.", colname,"'))) AS 'val' FROM mytable GROUP BY Label") SEPARATOR " UNION ")
       INTO @sql
FROM
(WITH RECURSIVE data AS (
  SELECT attr_details,JSON_VALUE(JSON_KEYS(attr_details), '$[0]') AS colname, 0 AS idx FROM mytable
  UNION
  SELECT attr_details,JSON_VALUE(JSON_KEYS(attr_details), CONCAT('$[', d.idx + 1, ']')) 
  AS colname, d.idx + 1 AS idx FROM data AS d
  WHERE d.idx < JSON_LENGTH(JSON_KEYS(attr_details)) - 1
) SELECT colname
FROM data
GROUP BY colname) V;

PREPARE stmt FROM @sql;
EXECUTE stmt;;

现在我尝试像下面这样在 larvel 中进行转换

$PDO=DB::connection('mysql')->getPdo();
            $stmt = $PDO->prepare(<<<_OUT
SET @sql = NULL;

SELECT GROUP_CONCAT(CONCAT("SELECT '",colname,"' AS 'Label',GROUP_CONCAT(JSON_UNQUOTE(JSON_EXTRACT(attr_details,'$.", colname,"'))) AS 'val' FROM product_attributes GROUP BY Label") SEPARATOR " UNION ")
       INTO @sql
FROM
(WITH RECURSIVE data AS (
  SELECT attr_details,JSON_VALUE(JSON_KEYS(attr_details), '$[0]') AS colname, 0 AS idx FROM product_attributes
  UNION
  SELECT attr_details,JSON_VALUE(JSON_KEYS(attr_details), CONCAT('$[', d.idx + 1, ']')) 
  AS colname, d.idx + 1 AS idx FROM data AS d
  WHERE d.idx < JSON_LENGTH(JSON_KEYS(attr_details)) - 1
) SELECT colname
FROM data
GROUP BY colname) V;
_OUT
);
    $stmt->execute();

    $result = $stmt->fetchAll();
    echo "<pre>"; print_r($result); die;

我收到此错误 “语法错误，意外的 'SELECT' (T_STRING)，期待 ')'”，
谁能帮助我做错了什么

Answer 1

SELECT GROUP_CONCAT(CONCAT("SELECT
                           ^-- this quote must be escaped like this: \"

PHP 认为你的 SQL 字符串到此结束。

同时检查其他引号。

编辑： 其他选项可能是将整个 SQL 包装到单引号 (')，然后转义查询中的那些 (\')

Answer 2

1. 请首先检查您的报价。在代码"SELECT GROUP_CONCAT(CONCAT("SELECT 中，PHP 将其识别为完整的字符串 "SELECT GROUP_CONCAT(CONCAT(" 和未定义的 SELECT ' 与下一个字符串，没有连接。

至少对我来说，我的 IDE 将您的代码突出显示为不正确。要处理各种报价，请尝试使用该方法

$stmt = $PDO->prepare(<<<_OUT
SELECT * FROM `table` WHERE "1";
_OUT
);

1. 尝试编写不带@sql 变量、不带PREPARE stm 和不带EXECUTE stm 的请求。我认为，PDO 将自己处理准备和执行。

   $stmt = $PDO->prepare(

   $stmt->执行(); $stmt->fetchAll();

2. 尝试使用 Laravel 方法：DB::select(DB::raw($sql));