Subquery returns more than 1 row ???

Developers Programming
#1

Hello all,
I’m trying to use this sql to sincronize details rows and master data:

UPDATE orders_details INNER JOIN orders ON orders_details.Id_Ord = orders.Id_Ord
SET orders_details.OrderID = ( SELECT orders.OrderID FROM orders WHERE orders_details.Id_Ord = orders.Id_Ord )

I got this error…

#1242 - Subquery returns more than 1 row

What does it means ?

Is it correct to add on sub query …
GROUP BY orders_details.Id_Ord

In this way it do not give error but I don’t know if it’s correct

#2

You are using an update which means that the subquery is only allowed to return one row as you are updating only one row. Appearantly your subquery returns more and thus the database doesn’t know which record to use for update. Ordersdetails are probabely the list of items you have on your order, so in this case all will have the same Id_Ord. For mysql you could apply a limit 0,1 to limit the subselect to one record only.

#3

OK . Thanks !!