使用嵌套選擇查詢更新查詢

Question

在這裏，我有一些學生信息表中。誰授權值默認爲0。 檢查一些條件我組的一些學生和更新也值爲1

只有那些學生誰符合一定條件即

select * from studentA 
where schName ='IES DADAR' and lang = 'E' 

[1]: http://rk.somee.com/untitled.jpg 

我用下面的嘗試之後代碼，但它不是過濾按我給出的條件，而不是它的變化的每一個同學的授權值設置爲1

update studentA 
set Authorized = '1' 
where Authorized IN 
(select Authorized from studentA 
where schName ='IES DADAR' and lang = 'E') 

你可以建議我的另一種方法爲好。

Answer 1

嘗試

update studentA 
set Authorized = '1' 
where schName ='IES DADAR' 
and lang = 'E' 

Answer 2

子查詢

select Authorized from studentA 
where schName ='IES DADAR' and lang = 'E' 

返回0，因此您的實際查詢變得

update studentA 
set Authorized = '1' 
where Authorized IN ('0') 

從而更新表中的每一行。

所以，它應該是

update studentA 
set Authorized = '1' 
where schName ='IES DADAR' and lang = 'E'