SQLize | PHPize | SQLtest

create table client_1 (id int, FIO text, dBirth date); create table client_2 (id int, FIO text, dBirth date); insert into client_1 values (100, 'Ivanov', '1990-05-17'), (101, 'Petrov', null), (103, 'Simonov', null), (106, 'Kozlov', '2020-01-01'), (107, 'Hohlov', '2020-01-01'); insert into client_2 values (100, 'Ivanov', null), (101, 'Petrov', '1990-05-17'), (105, 'Chernov', null), (106, 'Kozlov', null), (107, 'Hohlov', '2020-01-01'); select t1.id, t1.FIO, coalesce(t1.dBirth, t2.dBirth) as dBirth from client_1 t1 left join client_2 t2 using(id) where t1.dBirth is null or t2.dBirth is null; select t1.id, t1.FIO, coalesce(t1.dBirth, t2.dBirth) as dBirth from client_1 t1 full outer join client_2 t2 using(id) where t1.dBirth is null or t2.dBirth is null; select t1.id, t1.FIO, coalesce(t1.dBirth, t2.dBirth) as dBirth from client_1 t1 left join client_2 t2 using(id) -- where t1.dBirth is null or t2.dBirth is null union select t1.id, t1.FIO, coalesce(t1.dBirth, t2.dBirth) as dBirth from client_2 t1 left join client_1 t2 using(id); -- where t1.dBirth is null or t2.dBirth is null; select t1.id, t1.FIO, coalesce(t1.dBirth, t2.dBirth) as dBirth from client_1 t1 left join client_2 t2 using(id) where t1.dBirth is null or t2.dBirth is null union select t1.id, t1.FIO, coalesce(t1.dBirth, t2.dBirth) as dBirth from client_2 t1 left join client_1 t2 using(id) where t1.dBirth is null or t2.dBirth is null;