jep

Ok Psycho, now I've resolved the UNION clause and show what I need. I'm thinking about your consideration and making some tests. thank you!

I've already tried to make an UNION command but without result (how can put different name of columns in the four Select?)

Thank for answer Psycho! You're right but I cant create (merge) the service tables (servA, servB, serC, servD) in one because they are very difference each other*. servA contains information about course in a classroom servB contains information about consultancy servC contains information about elearning servD contains information about voucher They have a lot of different field and my example question are a simplification of them with only some common field.

it's impossible or it's too simple?

Hi to everyone and sorry for my bad english... there is a table, ServErog (service) wich is releaded to other 4 tables ServA, ServB, ServC, ServD (they are different non uniformable services) with two key, servtype (type of service) and type_id (numeric id from one of the 4 service table) Structure (simplyficaded): ServErog mysql> select * from ServErog +----+-------+----------+------+ | idSE | servtype | type_id | +----+-------+----------+------+ | 1 | 1 | 1 | | 2 | 2 | 1 | | 3 | 4 | 1 | | 4 | 3 | 1 | | 5 | 1 | 2 | +----+-------+----------+-------+ ServA mysql> select * from ServA +----+-------+----------+------+ | idSA | service_code | type | |+----+-------+----------+------+ | 1 | codice bla | 1 | | 2 | codice ecc | 1 | | 3 | bla bla | 1 | +----+-------+----------+------+ ServB mysql> select * from ServB +----+-------+----------+------+ | idSB | service_code | type | +----+-------+----------+------+ | 1 | codice bla | 2 | | 2 | codice ecc | 2 | | 3 | bla bla | 2 | +----+-------+----------+------+ ServC mysql> select * from ServC +----+-------+----------+------+ | idSC | service_code | type | +----+-------+----------+------+ | 1 | codice bla | 3 | | 2 | codice ecc | 3 | | 3 | bla bla | 3 | +----+-------+----------+------+ ServD mysql> select * from ServD +----+-------+----------+------+ | idSA | service_code | type | +----+-------+----------+------+ | 1 | codice bla | 4 | | 2 | codice ecc | 4 | | 3 | bla bla | 4 | +----+-------+----------+------+ Left Join Select ServErog.idSE, ServErog.servtype, ServErog.typeid, ServA.idSA, ServA.type, ServB.idSB, ServB.type, Serv.idSA, Serv.type, ServD.idSA, ServD.type From ServErog Left Join ServA On ServErog.servtype = ServA.type And ServA.idSA = ServErog.typeid Left Join ServB On ServErog.servtype = ServB.type And ServB.idSB = ServErog.typeid Left Join ServC On ServErog.servtype = ServC.type And ServC.idSC = ServErog.typeid Left Join ServD On ServErog.servtype = ServD.type And ServD.idSD = ServErog.typeid Order By ServErog.idSE +----+-------+----------+------+------+------+---------+ | idSE | servtype | type_id | idSA | idSB | idSC | idSD | +----+-------+----------+------+------+------+---------+ | 1 | 1 | 1 | 1 | null | null | null | | 2 | 2 | 1 | null | 1 | null | null | | 3 | 4 | 1 | null | null | null | 1 | | 4 | 3 | 1 | null | null | 1 | null | | 5 | 1 | 2 | 2 | null | null | null | +----+-------+----------+------+------+ This retur all records releaded with ServErog. Perfect! Now I need to show all record from ServA, ServB, ServC, ServD NOT PRESENT in ServErog. It's like an inverse of the precedent Join. I've tried with right join, with idSE is null but without result This is what I looking for this example: +----+-------+----------+------+ | idSA | idSB | idSC | idSD| +----+-------+----------+------+ | 3 | null | null | null | | null | 2 | null | null | | null | 3 | null | null | | null | null | 2 | null | | null | null | 3 | null | | null | null | null | 2 | | null | null | null | 3 | +----+-------+----------+------+