如何在SQL中做最大计数部分？

Question

I was told to Find out which occupation has the greatest number of patients with conditionID=MC8 I dk how to do the greatest part..... Here my code right now

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

You should approach these types of queries using regular joins and then add additional factors. The following gets the count of patients for each occupation with that condition:

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;

If you want the top row, that depends on the database. It might be select top 1 , limit 1 at the end, fetch first 1 rows only at the end, or even something else.