如何在理論中使用mysql變量

Question

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

我想通過學說執行此查詢，但出現以下錯誤

[Doctrine \\ DBAL \\ Driver \\ PDOException] SQLSTATE [42000]：語法錯誤或訪問沖突：1064您的SQL語法有錯誤；該錯誤可能會導致錯誤。 檢查與您的MariaDB服務器版本相對應的手冊以在第1行的'@counter：= 0'附近使用正確的語法

這是我的代碼

$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

大多數SQL API在沒有額外配置的情況下都不允許多個語句。 您需要將它們作為單獨的語句傳遞：

$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);