Question

i am a beginner in sql … i search accross the web to find a solution for my problem but i could not found any suitable answer .

i have the following tables in sql server database ::

Room Block BoxSet

Room idField , RoomNumber

Block RoomID : foreign key to Room Table

BoxSet BlockID : foreign key to Block Table

i have been trying to find a way to select records in BoxSet Table according to Room Table RoomNumber Field.

for example:i want to select all records in BoxSet Table which belongs to RoomNumber=1.

Answer 1

SELECT BS.* 

FROM Room R 
INNER JOIN Block B ON R.RoomId = B.RoomId 
INNER JOIN BoxSet BS ON B.BlockId = BS.BlockId

WHERE R.RoomNumber = 1;

This is a very basic usage of the JOIN functionality present in every relational database.