Question

我被告知找出条件ID = MC8的患者数量最多的职业我dk怎么做最大的部分..... 现在我的代码

SELECT occupation
FROM Patient
WHERE EXISTS                  
(SELECT PatientID FROM PatientMedcon
    Where conditionID=’MC8’)    
GROUP BY occupation
HAVNG count(occupation) = (Select max(occupation)
From Patient

Answer 1

您应该使用常规联接来处理这些类型的查询，然后添加其他因素。以下是每种职业患者的病情计数：

SELECT occupation, COUNT(*)
FROM Patient p JOIN
     PatentMedcon pm
     ON p.PatientId = pm.PatientId and
        pm.conditionId = 'MC8'
GROUP BY occupation
ORDER BY COUNT(*) DESC;

如果你想要顶行，那取决于数据库。最后可能是select top 1，limit 1，最后是fetch first 1 rows only，甚至可能是其他内容。

如何在SQL中执行max count部分？

1 个答案: