別名加入後的2個表的產品

Question

沒關係，所以事情是我有2個不同的表，我使用內部連接來獲得2個表的共同點。我可以在加入後很好地對新列進行別名，但我需要在新列中計數並顯示最常見的值。我無法想出辦法做到這一點。但是，我通過創建新表並計算出現次數，發出值並刪除表來找到解決辦法。我真的想知道什麼是正確的方式做，這...這裏是我的代碼：

create table result as 
(
    select department.Dcode as de_code, department.Dname as de_name 
    from (department join enroll on department.Dcode = enroll.Dcode) 
); 

SELECT  result.de_name, 
      COUNT(result.de_name) AS occurr 
    FROM  result 
    GROUP BY result.de_name 
    ORDER BY occurr DESC 
    LIMIT 1; 

drop table result; 

Answer 1

你可以試試這個：

SELECT result.de_name, COUNT(result.de_name) AS occurr 
FROM 
(select department.Dcode as de_code, department.Dname as de_name from department join enroll on department.Dcode = enroll.Dcode) as result 
GROUP BY result.de_name 
ORDER BY occurr DESC 

這裏result是由INNER JOIN返回的記錄別名。