sql - query last Renewal of licences -


suppose have client renewal of licences every year. how query last year clients had renew licences per section... tried code , worked fine produce max year in section i.e 2014 though there clients have no renew licences since 2012...

select @last_expired_date = max(expired_license_date)     entrepreneur     right outer join firm_info         on entrepreneur.entre_id = firm_info.entre_id     right join section         on firm_info.section_id = section.section_id     right join license         on firm_info.firm_no = license.firm_no     right join license_operations         on license.license_serial = license_operations.license_serial     section.section_id = @section_no     group license.license_serial 

you need add client name select , group by clause, give list of clients , latest year have renewed license.

as note: use alias table names in joins. helps identify columns come tables. additionally avoid using right join because can make harder understand data getting.


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