嵌套的SQL选择语句

Question

谁能告诉我以下sql查询出了什么问题？

Select *, 
(SELECT [DiseaseID], COUNT(*) AS [Rank] FROM [DiseaseSymptom] WHERE
    ([SymptomID] IN(1, 5)) GROUP BY [DiseaseID] ORDER BY [Rank] DESC)
FROM Disease WHERE GenderID in (1, 3)

我有2张桌子，一张包含疾病和与之相关的性别

疾病

+-----------+-------------------+----------+
| DiseaseID |    DiseaseName    | GenderID |
+-----------+-------------------+----------+
|         1 | Fever             |        3 |
|         2 | Flu               |        3 |
|         3 | Lady Disease      |        2 |
|         4 | Gentlemen Disease |        1 |
+-----------+-------------------+----------+

性别1 =男性，2 =女性，3 =普通

还有像这样的症状疾病矩阵

疾病症状

+-----------+-----------+----------+
| DiseaseID | SymptomID | DissymID |
+-----------+-----------+----------+
|         1 |         1 |        1 |
|         1 |         2 |        3 |
|         1 |         4 |        4 |
|         2 |         1 |        5 |
|         2 |         3 |        9 |
|         2 |         4 |        6 |
|         2 |         5 |        7 |
+-----------+-----------+----------+

我从用户那里得到症状，并在DiseaseSymptom表中将其匹配，并根据匹配的症状数对其进行排名（内部sql语句）

在外部陈述中，我只想从内部陈述中获取结果并评估它是否属于特定性别。 我尝试运行上述查询时遇到的错误是

The ORDER BY clause is invalid in views, inline functions, derived tables, subqueries, and common table expressions, unless TOP or FOR XML is also specified.

Answer 1

您正在使用group by的子查询。 您的意图是拥有一个相关的子查询。 问题是子查询返回的行多。 我认为这是您想要的：

Select d.*, 
      (SELECT COUNT(*) AS [Rank]
       FROM [DiseaseSymptom] ds
       WHERE [SymptomID] IN (1, 5)) AND ds.DiseaseId = d.DiseaseId
      )
FROM Disease d
WHERE GenderID in (1, 3);

Answer 2

select子句中的子查询只能生成标量值，而不是具有多列或多行的结果集。 如果两者都需要，则将子查询放在from子句中（正确关联），并在select子句中引用两个不同的vqlues

 Select d.*, z.DeseaseId, z.Rank
 FROM Disease d
     join (SELECT DiseaseID, COUNT(*) Rank
           FROM DiseaseSymptom
           WHERE SymptomID IN(1, 5) 
           GROUP BY DiseaseID) Z
       On z.DeseaseId = d.DeseaseId
 WHERE GenderID in (1, 3)
 Order By z.Rank

Answer 3

您应该像这样使用通用表表达式（cte）：

    with cte as (SELECT [DiseaseID], GenderID, COUNT(*) AS [Rank] FROM [DiseaseSymptom] WHERE
    ([SymptomID] IN(1, 5)) GROUP BY [DiseaseID],GenderID ORDER BY [Rank] DESC)
    select * FROM cte WHERE GenderID in (1, 3)

希望这个帮助;）

Answer 4

确实不需要嵌套查询，只需联接和过滤即可

SELECT d.DiseaseID, d.DiseaseName, d.GenderID
     , Symptoms = Count(ds.SymptomID)
FROM   Disease d
       INNER JOIN DiseaseSymptom ds ON d.DiseaseID = ds.DiseaseID
WHERE  ds.SymptomID IN (1, 5)
  AND  d.GenderID IN (1, 3)
GROUP BY d.DiseaseID, d.DiseaseName, d.GenderID
ORDER BY Count(SymptomID) Desc

SQLFiddle演示