Question

SELECT STATNO FROM ENQUIRY  WHERE ID=12;

Returns: 100,102,110

SELECT STATNO FROM ENQUIRY  WHERE ID=16;

Returns: 102,112,118

 SELECT STATNO FROM ENQUIRY  WHERE ID=21;

Returns: 101,102,120

I need a query that combines the above and returns the common data: 102.

Answer 1

drop table if exists enquiry;
create table enquiry (id integer, statno integer);
insert into enquiry values 
(12,100),(12,102),(12,110),
(18,102),(18,112),(18,118),
(21,101),(21,102),(21,120);

select distinct statno from enquiry where 
statno in (select statno from enquiry where id=12)
and statno in (select statno from enquiry where id=18)
and statno in (select statno from enquiry where id=21)
;