更新2表的查询
问题描述：
大家好吧
i下面有这个查询
Hi All
i have this Query Below
string updateReq = "UPDATE Student SET Student.ID_Request = Request.ID_Request FROM Request where Student.St_Code=Request.St_Code INNER JOIN Request ON Student.ID_Request = Request.ID_Request";
但是当我执行此操作时出现此错误：
but when i excute this i get this error :
The objects "Request" and "Request" in the FROM clause have the same exposed names. Use correlation names to distinguish them.
我该如何解决这个问题？
我尝试了什么：
i尝试选择临时表中的记录但它不起作用或者我可以这样做错误
how can i solve this ?
What I have tried:
i tried to select the records in the temp table but it doesn't work or maybe i do it wrong
string select = "SELECT * INTO #TempTable FROM Student s where ID_Request IS NULL";
string updateReq = "UPDATE TempTable SET s.ID_Request = Request.ID_Request FROM Request where Student.St_Code=Request.St_Code INNER JOIN Request ON Student.ID_Request = Request.ID_Request";
当我执行这些字符串时我得到同样的错误
when i excute these string i get the same error
答
UPDATE Student SET Student.ID_Request = R1.ID_Request
FROM Request R1
INNER JOIN Request R2
ON (Student.ID_Request = R2.ID_Request)
INNER JOIN Student
ON (Student.St_Code=R2.St_Code)
你必须区分同一个表的两个实例。我会尝试帮助，但我在手机上这样做...
You have to distinguish between the two instances of the same table. I will try to help but I'm doing this on a phone...
string updateReq = "UPDATE Student SET Student.ID_Request = R1.ID_Request FROM Request R1 where Student.St_Code=Request.St_Code INNER JOIN Request R2 ON Student.ID_Request = R2.ID_Request";我无法对此进行测试，但请注意，我已经为每个表提供了别名。
I can't test this but note that I've given the tables an alias each.