如何在MySQL更新新增的列

Question

嗨

我添加了一個新欄目「時間」和我想更新該列。我寫了下面的代碼，但沒有工作。以下代碼的問題是什麼？

UPDATE OFFICER 
SET HOURS=5 AND HOURS=4 AND HOURS=4 AND HOURS=3 
WHERE NAME IN('KASUN','MANEL','LALA'); 

Answer 1

如果你只是想正是這些值來填充新列，你可以使用一個UPDATE有CASE WHEN，如：

UPDATE OFFICER 
    SET HOURS = CASE WHEN NAME = 'KASUN' THEN 5 
        WHEN NAME = 'MANEL' THEN 4 
        WHEN NAME = 'LALA' THEN 3 
       END 
WHERE NAME IN('KASUN','MANEL','LALA'); 
; 

如果你想填充與行隨機數，你可以只產生這樣一個隨機數：

UPDATE OFFICER 
    SET HOURS = ABS(Checksum(NewID()) % 6) + 1 
WHERE NAME IN('KASUN','MANEL','LALA'); 
; 

的ABS(Checksum(NewID()) % 6) + 1將產生1和6

Answer 2

你不能在同一時間，你可以爲一個列設置多個值，只需設置一個值，這樣

UPDATE OFFICER SET HOURS = 5 
WHERE NAME IN('KASUN','MANEL','LALA'); 

Answer 3

之間的隨機數你猜怎麼着，我想你可能需要CASE WHEN：

UPDATE OFFICER 
SET HOURS = CASE WHEN NAME = 'KASUN' THEN 5 
       WHEN NAME = 'MANEL' THEN 4 
       WHEN NAME = 'LALA' THEN 3 
       ELSE HOURS 
      END; 

Answer 4

如果會有條件意味着您可以根據條件設置多個值，例如：。。。。。。

UPDATE OFFICER SET HOURS = CASE WHEN NAME= 'KASUN' THEN 5 
        WHEN NAME= 'MANEL' THEN 4 
        WHEN NAME= 'LALA' THEN 3 END WHERE NAME IN('KASUN','MANEL','LALA'); 

其他明智的，你可以像如下─

UPDATE OFFICER SET HOURS=5 WHERE NAME='KASUN'; 

    UPDATE OFFICER SET HOURS=4 WHERE NAME ='MANEL'; 

    UPDATE OFFICER AND HOURS=3 WHERE NAME='LALA';