Update fails because Subquery returned more than 1 value

问题

I Get the following error when i try to update my table although there's n't any sub query :

Subquery returned more than 1 value. This is not permitted when the subquery follows =, !=, <, <= , >, >= or when the subquery is used as an expression. 

---

MY QUERY :

UPDATE  t1 
SET t1.modified = 2
FROM TransActions AS t1
INNER JOIN Ruser R
ON t1.USERID = r.USERID
WHERE  r.dep_code = 54 and r.dep_year =2014
and YEAR(t1.checktime) =2016 and MONTH(t1.checktime) =1 and  t1.modified   = 0

---

The data selected like this :

USERID  empNum
3090    25
3090    25
2074    464

---

According to the comments my update trigger :

after update 
as

declare @userid int , @date date 


if (select userid from inserted)<>(select userid from deleted )
raiserror ('YOU ARE NOT ALLOWED TO PERFORME THIS ACTION',10 , 1)
ELSE
begin 
    set nocount on;

    set @userid = (select userid from inserted)
    set @date = (select convert(date , checktime) from inserted)


    exec calc_atten @date , @userid 
end

回答1:

Triggers are executed per statement, not per row, that's the source of your error. Your trigger assumes that the inserted and deleted tables will only ever have one row, however that is simply wrong.
The number of rows in the inserted / deleted tables is the number of rows effected by the DML statement (update/insert/delete).

I don't know what the procedure calc_atten does, but you need to find a way to execute it's logic on a set level and not on scalar variables as it does now.

Your condition at the beginning of the trigger should be changed to fit a multi-row update. One way to do it is this: (I could probably write it shorter and better if I would have known the table's structure)

IF EXISTS (
    SELECT 1
    FROM deleted d 
    INNER JOIN inserted i
    ON d.[unique row identifier] = i.[unique row identifier]
    WHERE i.userId <> d.UserId
)

*[unique row identifier] stands for any column or column combination that is unique per row in that table. If the unique row identifier contains the UserId column then this will not work properly.

回答2:

Your query is ok. The problem is the trigger. inserted and deleted are tables (well, really views but that is irrelevant), so they can contain multiple rows.

Assuming that transactions has a primary key, you can check the update by doing

declare @userid int , @date date ;

if (exists (select 1
            from inserted i
            where not exists (select 1
                              from deleted d
                              where d.transactionid = i.transactionid and
                                    d.userid <> i.userid
                             )
           )
   )
begin
    raiserror ('Changing user ids is not permitted', 10 , 1);
end;
else begin 
    set nocount on;

    declare icursor cursor for select userid, checktime from inserted;
    open icursor;

    fetch next from icursor into @userid, @date;

    while not @@FETCH_STATUS = 0
    begin
        exec calc_atten @date, @userid 
        fetch next from icursor into @userid, @date;
    end;

   close icursor; deallocate icursor;
end;

Cursors are not my favorite SQL construct. But, if you need to loop through a table and call a stored procedure, then they are appropriate. If you can rewrite the code to be set-based, then you can get rid of the cursor.

回答3:

Try using distinct like this:

UPDATE  t1 
SET t1.modified = 2
FROM TransActions AS t1
INNER JOIN (select distinct userid from Ruser
            where r.dep_code = 54 and r.dep_year = 2014 ) R
ON t1.USERID = r.USERID
WHERE YEAR(t1.checktime) =2016 and MONTH(t1.checktime) =1 and  t1.modified   = 0

BTW - I don't see any subquery here, so its weird thats the error you get, I have a feeling the error doesn't occurs because of that part of the code.

回答4:

You can use distinct to return unique userid's:

UPDATE TransActions 
SET modified = 2
WHERE YEAR(checktime) = 2016
AND   MONTH(checktime = 1
AND   modified = 0
AND   userid IN ( SELECT DISTINCT userid FROM Ruser r WHERE  r.dep_code = 54 and r.dep_year =2014 );

来源：https://stackoverflow.com/questions/35253299/update-fails-because-subquery-returned-more-than-1-value