how to use an aggregate function
Date: 17 May 2003 09:35:02 -0700
Message-ID: <de0fa271.0305170835.49ea138c_at_posting.google.com>
Hello
Imagine if you would if I had a database like this:
DROP TABLE Customer;
CREATE TABLE Customer(
CustomerID int, Cname varchar(10), City varchar(10), PRIMARY KEY(CustomerID)
);
DROP TABLE Item;
CREATE TABLE Item(
ItemID int, UnitPrice int, PRIMARY KEY(ItemID)
);
DROP TABLE AOrder;
CREATE TABLE AOrder(
AOrderID int, Odate date, CustomerID int, Ird_Amt int, PRIMARY KEY(AOrderID), FOREIGN KEY(CustomerID) REFERENCES Customer(CustomerID)
);
DROP TABLE OrderItem;
CREATE TABLE OrderItem(
AOrderID int, ItemID int, Qty int, PRIMARY KEY(AOrderID, ItemID), FOREIGN KEY(AOrderID) REFERENCES AOrder(AOrderID), FOREIGN KEY(ItemID) REFERENCES Item(ItemID)
);
DROP TABLE Warehouse;
CREATE TABLE Warehouse(
WarehouseID int, Wcity varchar(10), PRIMARY KEY(WarehouseID)
);
DROP TABLE Shipment;
CREATE TABLE Shipment(
AOrderID int, WarehouseID int, ShipDate date, PRIMARY KEY(AOrderID, WarehouseID), FOREIGN KEY(AOrderID) REFERENCES AOrder(AOrderID), FOREIGN KEY(WarehouseID) REFERENCES Warehouse(WarehouseID)
);
INSERT INTO Customer VALUES(1, 'Jack', 'NeverLd'); INSERT INTO Customer VALUES(2, 'Jill', 'Wall'); INSERT INTO Customer VALUES(3, 'Emma', 'Desolat');
INSERT INTO AOrder VALUES(1, '1/1/2003', 1, 3); INSERT INTO AOrder VALUES(2, '1/1/2003', 3, 3);
INSERT INTO Item VALUES(1, 5); INSERT INTO Item VALUES(2, 5); INSERT INTO Item VALUES(3, 15); INSERT INTO OrderItem VALUES(1, 1, 1);
INSERT INTO OrderItem VALUES(1, 2, 5);
INSERT INTO OrderItem VALUES(1, 3, 15);
INSERT INTO OrderItem VALUES(2, 1, 2);
INSERT INTO OrderItem VALUES(2, 2, 5);
INSERT INTO Warehouse VALUES(1, 'Water fall'); INSERT INTO Warehouse VALUES(2, 'Fall vill');
INSERT INTO Shipment VALUES(1, 2, '1/1/2002'); INSERT INTO Shipment VALUES(2, 1, '1/1/2002');
How would I
List the name of customers who have paid an average of more then $6.
Produce a listing Cname, Avg_Paid
All I can think of is this.
SELECT Customer.Cname, AVG(Item.UnitPrice) AS Avg_Paid
FROM Customer
JOIN AOrder
ON Customer.CustomerID = AOrder.CustomerID
JOIN OrderItem
ON AOrder.AOrderID = OrderItem.AOrderID
JOIN Item
ON OrderItem.ItemID = Item.ItemID
GROUP BY Customer.Cname
;
I can't figure out how to limit it to over $6?
Thanks for any help. Received on Sat May 17 2003 - 18:35:02 CEST