如何在学说中使用mySQL变量

Question

https://stackoverflow.com/a/12772507/1507546

我想通过学说执行此查询，但是我在下面遇到错误

[学说 dbal driver pdoexception] SQLSTATE [42000]：语法错误或访问违规：1064您的SQL语法中有错误；检查与您的MariadB服务器版本相对应的手册，以获取合适的语法 '@counter：= 0'在第1行

这是我的代码

$sql = <<<S
    SET @counter = 0; 
    Select sub.orderid,sub.value,(@counter := @counter +1) as counter
    FROM
    (
        select orderid, 
          round(sum(unitprice * quantity),2) as value
        from order_details
        group by orderid
    ) sub
    order by 2 desc
    limit 10
S;
stmt = $this->_em->getConnection()->prepare($sql);
$stmt->execute();
return $stmt->fetchAll(AbstractQuery::HYDRATE_ARRAY);

Answer 1

大多数SQL API不允许没有额外配置的多个语句。您需要将它们作为单独的陈述传递：

$this->_em->getConnection()->exec("SET @counter = 0"); // May need tweaking, I'm not familiar with Doctrine
$sql = <<<S
    Select sub.orderid,sub.value,(@counter := @counter +1) as counter
    FROM
    (
        select orderid, 
          round(sum(unitprice * quantity),2) as value
        from order_details
        group by orderid
    ) sub
    order by 2 desc
    limit 10
S;
stmt = $this->_em->getConnection()->prepare($sql);