如何使用MySQL的变量理论

Question

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

我想通过理论来执行这个查询，但我发现下面的错误

[主义\ DBAL \驱动程序\ PDOException] SQLSTATE [42000 ]：语法错误或访问冲突：1064您的SQL语法错误;检查对应于您MariaDB的服务器版本正确的语法附近 使用“@counter：= 0”手动位于第1行

这里是我的代码

$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的不要不需要额外配置就可以允许多个语句您需要将它们作为单独的语句传入：

$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);