MULTIPLE TABLES IN SQL

Question

How to write sql query for the following:
Distributor (Dno, Dname, Daddress, Dphone)
Item (Itemno, Itemname, Colour, Weight), Dist_Item(Dno, Itemno, Qty)

a. Find out distributors, who have supplied item number 01.
b. Find out details of item supplied by distributor 01.

Answer 1

a.
SELECT Item.Itemno, Distributor.Dname, Distributor.Dno from Dist_Item
JOIN Distributor on Distributor.Dno = Dist_Item.Dno
JOIN Item on Distributor.Itemno = Dist_Item.Itemno WHERE Dist_Item.Itemno = '1';

b.
SELECT Distributor.Dno, Item.Itemno, Item.Itemname, Item.Colour, Item.Weight from Dist_Item
JOIN Distributor on Distributor.Dno = Dist_Item.Dno
JOIN Item on Item.Itemno = Dist_Item.Itemno
WHERE Dist_Item.Dno = '1';

Answer 2

https://www.w3schools.com/sql/sql_join.asp

May help you