Subject join question
Author Check_Mail

Hello @ll,


I have a small question.


Table A


NrWorker ineger


Active 0 or 1


Table B


NrWorker integer





Now I would like to get all NrWorker from Table A with Active 1 and the ValueWorkerMonth from the Table B (from the current month)


This is like


Select a.nrworker, b.valueworkermonth from table A left join table B on a.nrworker = b.nrworker where = 1 and b.year = 2017 and b.month = 4


Fine, but I would like also all Worker (NrWorker from Table A) where are not present in Table B in this month.


Table A

NrWorker 12

NrWorker 13

NrWorker 14


Table B

NrWorker 12

Year  2017

Month 4


I would like to get not only Worker 12,  rather 13 and 14 too.


How can I realize it in Firebird?


Thank you