我正在學習 MySQL。在已經創建的表中，我添加了一個列（類）。現在我想在類列中添加資料。要在單行中添加資料，我使用了以下代碼：
update stu SET WHERE id = 1;
我不想逐行更新每一行，而是想更新類列中的所有行，我使用了以下命令
update stu SET
class="5th" WHERE id = 2
class="6th" WHERE id = 3
class="6th" WHERE id = 4
class="7th" WHERE id = 5
class="7th" WHERE id = 6
class="8th" WHERE id = 7
運行命令后，顯示以下錯誤
update stu SET WHERE id = 2 WHERE id = 3 WHERE id = 4 WHERE id = 5 WHERE id = 6 WHERE id = 7 Error Code: 1064. You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ' WHERE id = 3 WHERE id = 4 WHERE id = 5 class' at line 3 0.000 sec
誰能告訴我如何一次更新行？
uj5u.com熱心網友回復：
單個更新通常只能有一個WHERE子句。但是，您可以使用CASE運算式進行更新：
UPDATE stu
SET class = CASE id WHEN 2 THEN '5th'
WHEN 3 THEN '6th'
WHEN 4 THEN '6th'
WHEN 5 THEN '7th'
WHEN 6 THEN '7th'
WHEN 7 THEN '8th' END
WHERE id BETWEEN 2 AND 7;
轉載請註明出處，本文鏈接：https://www.uj5u.com/houduan/522267.html
標籤：mysql