Question

这是我的SQL查询：

SELECT pa.* 
FROM pa 
WHERE pa.id IN ( SELECT prerequis.idpa 
                 FROM prerequis WHERE prerequis.id2a = 18) 
UNION ALL 

SELECT pa.* 
FROM pa 
WHERE pa.id IN ( SELECT prerequis.idpa 
                 FROM prerequis WHERE prerequis.id2a = 15) 
UNION ALL 

SELECT pa.* 
FROM pa 
WHERE pa.id IN ( SELECT prerequis.idpa 
                 FROM prerequis WHERE prerequis.id2a =32);

这给了我一个表副本中的元素列表。现在我想根据第一个结果中的冗余情况得到相同的列表？（最常见的顶部）。

提前感谢大家的帮助：）

Answer 1

首先你不需要UNION ALL

SELECT pa.*, COUNT(*)
FROM pa 
INNER JOIN prerequis pr
  ON pa.id = pr.idpa
WHERE pr.id2a IN (15, 18, 32)
GROUP BY pa.id
ORDER BY COUNT(*) DESC

如何按重复次数排序SQL结果？

1 个答案: