通过联接3个表来更新表

Question

i have 3 tables:

• tblproduct (pro_Id, qty, unitprice)
• tblorderdetails (order_id, pro_Id, qty)
• tblorder (order_id, totalAmount)

i intend joining these tables to as to update the totalAmount in the tblorder table . This is my query using MySql console:

UPDATE o
SET o.totalAmount = p.unitprice * d.qty
FROM tblorder o INNER JOIN tblorderdetails d
on o.order_id = d.order_id
INNER JOIN tblproduct p
on p.pro_Id = d.pro_Id;

This is the error i get:

ERROR 1064 (42000): 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 'from tblorder o inner join tblorderdetails d

Answer 1

The syntax is not correct and it should be as

UPDATE  tblorder o
INNER JOIN tblorderdetails d
on o.order_id = d.order_id
INNER JOIN tblproduct p
on p.pro_Id = d.pro_Id
SET o.totalAmount = p.unitprice * d.qty ;