- create table foo (x char(10) primary key);
- insert into foo values ('a_b');
- insert into foo values ('ac_b');
- insert into foo values ('aa_b');
- insert into foo values ('aab');
- insert into foo values ('a_ab');
- insert into foo values ('a_a');
- insert into foo values ('b_a');
- insert into foo values ('ba');
- insert into foo values ('b__a');
- select * from foo where x = 'a_ab';