-- if not defined
insert into taxkeys(chart_id,tax_id,taxkey_id,startdate) SELECT (SELECT reverse_charge_chart_id FROM tax WHERE taxkey = '18' and rate = 0.07 and reverse_charge_chart_id is not null),0,0,'1970-01-01' WHERE NOT EXISTS
-- if not defined
insert into taxkeys(chart_id,tax_id,taxkey_id,startdate) SELECT (SELECT reverse_charge_chart_id FROM tax WHERE taxkey = '18' and rate = 0.07 and reverse_charge_chart_id is not null),0,0,'1970-01-01' WHERE NOT EXISTS