Question

I’ve been having trouble coming up with a proper query to handle this situation in SQL Server.

There are two tables, Warehouse and Transfer:

Warehouse

• wh_id(PK)
• wh_name

Transfer

• transfer_id(PK)
• transfer_from(FK)
• transfer_to (FK)

I need a query to return:

• transfer_id
• transfer_from – Name, not id
• transfer_to – Name, not id

What I’ve tried so far:

SELECT T.transfer_id, WH.wh_name, T.transfer_to
FROM transfer AS T INNER JOIN warehouse AS WH
ON T.transfer_from = WH.wh_id

This only gives the name for the transfer_from not the transfer_to. I’ve had a need for a similar query but my level of SQL expertise is low and I just don’t know how to approach this problem. Any guidance is greatly appreciated.

Answer 1

you need to join the table warehouse twice because you need to get the equivalent name fro two columsn in your transfer table.

SELECT  a.transfer_ID,
        b.wh_name AS from_name,
        c.wh_name AS to_Name
FROM        transfer a
            INNER JOIN warehouse b
                ON a.transfer_from = b.wh_id
            INNER JOIN warehouse c
                ON a.transfer_to = c.wh_id