如何組合GROUP BY，ORDER BY和HAVING

Question

如何正確地將此語句組合在一起。

SELECT *, COUNT(*) 
FROM user_log 
GROUP BY Email 
ORDER BY UpdateDate DESC 
HAVING COUNT(*) > 1 

讓我知道

Answer 1

ORDER BY總是最後...

但是，你需要選擇你真正想要領域，然後由他們只選擇那些和組。 SELECT *和GROUP BY Email會給你隨機數所有的領域，但Email。由於創建的問題，大多數RDBMS甚至不允許你這樣做，但MySQL是例外。

SELECT Email, COUNT(*) 
FROM user_log 
GROUP BY Email 
HAVING COUNT(*) > 1 
ORDER BY UpdateDate DESC 

Answer 2

步驟使用組通過，通過...

Select Attitude ,count(*) from Person 
group by person 
HAving PersonAttitude='cool and friendly' 
Order by PersonName. 

Answer 3

你的代碼應該是包含由和順序設置在具有WHILE之前group by和having：

SELECT Email, COUNT(*) 

FROM user_log 

WHILE Email IS NOT NULL 

GROUP BY Email 

HAVING COUNT(*) > 1 

ORDER BY UpdateDate DESC