Question

trying to build a query from a few tables here, and getting stumped on finalizing it:

Table 1 (circuits)

t1.circuit_id
t1.circuit_name

(sample data)

1234, test1
1235, test2
1236, test3

Table 2 (accounts)

t2.account_id
t2.account_username

(sample data)

100, user1
101, user2
102, user3

Table 3 (assignments)

t3.circuit_id
t3.assignment1 (references table 2 (account_id))
t3.assignment2 (references table 2 (account_id))
t3.assignment3 (references table 2 (account_id))

(sample data)

1234, 100, 101, 102
1235, 101, 101, 101
1236, 102, 102, 102

What I’m after is a result like following:

t1.circuit_id, t3.assignment1, t2.account_username, t3.assignment2, t2.account_username, t3.assignment3, t2.account_username.

1234, 100, user01, 101, user02, 102, user03
1235, 101, user02, 101, user02, 101, user02
1236, 102, user03, 102, user03, 102, user03

Many thanks,
–a

Answer 1

SELECT  t3.circuit_id, t3.assignment1, t21.account_username, t3.assignment2, t22.account_username, t3.assignment3, t23.account_username
FROM    t3
LEFT JOIN
        t2 t21
ON      t21.account_id = t3.assigment1
LEFT JOIN
        t2 t22
ON      t22.account_id = t3.assigment2
LEFT JOIN 
        t2 t23
ON      t23.account_id = t3.assigment3