主義CASE WHEN然後是NULL

Question

我有一個存儲庫功能，我想使用CASE WHEN然後ELSE，但教義不允許在ELSE NULL。當然，我GOOGLE了，但我找不到答案如何避免它。

public function countAverageOdd($user) { 
    return $this->getEntityManager() 
        ->createQuery(' 
          SELECT 
           avg(
            CASE 
             WHEN p.homeAway = \'h\' AND p.moneyline IS NOT NULL THEN m.home 
             WHEN p.homeAway = \'d\' AND p.moneyline IS NOT NULL THEN m.draw 
             WHEN p.homeAway = \'e\' AND p.moneyline IS NOT NULL THEN m.away 
             WHEN p.homeAway = \'h\' AND p.spread IS NOT NULL THEN s.home 
             WHEN p.homeAway = \'e\' AND p.spread IS NOT NULL THEN s.away 
             WHEN p.homeAway = \'h\' AND p.total IS NOT NULL THEN t.over 
             WHEN p.homeAway = \'e\' AND p.total IS NOT NULL THEN t.under 
            ELSE NULL 
            END 
            ) 
          FROM 
           AppBundle:Predictions p 
           LEFT JOIN p.moneyline m 
           LEFT JOIN p.spread s 
           LEFT JOIN p.total t 
          WHERE p.user = :user ') 
        ->setParameter(":user", $user) 
        ->setMaxResults(1) 
        ->getSingleScalarResult(); 
} 

錯誤：[語法錯誤] 0行，列900 ：錯誤：意外 'NULL'

https://github.com/doctrine/doctrine2/issues/3160

doctrinebot評論了2013年5月22日

問題以分辨率「不會修復」關閉

請給我建議。

Answer 1

我設法通過傳遞空值作爲參數來繞過主義邏輯檢查。這是一個黑客攻擊，但它似乎是唯一有效的工具。

public function countAverageOdd($user) { 
    return $this->getEntityManager() 
        ->createQuery(' 
          SELECT 
           avg(
            CASE 
             WHEN p.homeAway = \'h\' AND p.moneyline IS NOT NULL THEN m.home 
             WHEN p.homeAway = \'d\' AND p.moneyline IS NOT NULL THEN m.draw 
             WHEN p.homeAway = \'e\' AND p.moneyline IS NOT NULL THEN m.away 
             WHEN p.homeAway = \'h\' AND p.spread IS NOT NULL THEN s.home 
             WHEN p.homeAway = \'e\' AND p.spread IS NOT NULL THEN s.away 
             WHEN p.homeAway = \'h\' AND p.total IS NOT NULL THEN t.over 
             WHEN p.homeAway = \'e\' AND p.total IS NOT NULL THEN t.under 
            ELSE :null 
            END 
            ) 
          FROM 
           AppBundle:Predictions p 
           LEFT JOIN p.moneyline m 
           LEFT JOIN p.spread s 
           LEFT JOIN p.total t 
          WHERE p.user = :user ') 
        ->setParameters(array(":user"=> $user,":null"=>NULL)) 
        ->setMaxResults(1) 
        ->getSingleScalarResult(); 

Answer 2

結帳出myql case operator documentation。該ELSE是可選的，因此你可以將其刪除

public function countAverageOdd($user) { 
    return $this->getEntityManager() 
        ->createQuery(' 
          SELECT 
           avg(
            CASE 
             WHEN p.homeAway = \'h\' AND p.moneyline IS NOT NULL THEN m.home 
             WHEN p.homeAway = \'d\' AND p.moneyline IS NOT NULL THEN m.draw 
             WHEN p.homeAway = \'e\' AND p.moneyline IS NOT NULL THEN m.away 
             WHEN p.homeAway = \'h\' AND p.spread IS NOT NULL THEN s.home 
             WHEN p.homeAway = \'e\' AND p.spread IS NOT NULL THEN s.away 
             WHEN p.homeAway = \'h\' AND p.total IS NOT NULL THEN t.over 
             WHEN p.homeAway = \'e\' AND p.total IS NOT NULL THEN t.under 

            END 
            ) 
          FROM 
           AppBundle:Predictions p 
           LEFT JOIN p.moneyline m 
           LEFT JOIN p.spread s 
           LEFT JOIN p.total t 
          WHERE p.user = :user ') 
        ->setParameter(":user", $user) 
        ->setMaxResults(1) 
        ->getSingleScalarResult();