Question

Table A
Table B
Tabls C1, C2 .... Cn : title field

relationship C INNER JOIN B LEFT JOIN A

query 
SELECT C1.title FORM C1 
INNER JOIN B on C1.c_id = B.c_id
LEFT JOIN A on B.b_id = A.b_id

Can it be merged into one query ?

Answer 1

I’m not sure I fully understand your question, but if C1, C2, …, Cn are all “parallel” tables, then perhaps a UNION does the trick:

SELECT C1.title AS title FROM C1 INNER JOIN B on C1.c_id = B.c_id LEFT JOIN A on B.b_id = A.b_id
UNION ALL
SELECT C2.title AS title FROM C2 INNER JOIN B on C2.c_id = B.c_id LEFT JOIN A on B.b_id = A.b_id
UNION ALL
...
UNION ALL
SELECT Cn.title AS title FROM Cn INNER JOIN B on Cn.c_id = B.c_id LEFT JOIN A on B.b_id = A.b_id