主义CASE WHEN然后是NULL

Question

我有一个存储库功能，我想使用CASE WHEN然后ELSE，但教义不允许在ELSE NULL。当然，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(); 
} 

错误：[语法错误] 0行，列900 ：错误：意外 'NULL'

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

doctrinebot评论了2013年5月22日

问题以分辨率“不会修复”关闭

请给我建议。

Answer 1

我设法通过传递空值作为参数来绕过主义逻辑检查。这是一个黑客攻击，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

结帐出myql case operator documentation。该ELSE是可选的，因此你可以将其删除

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();