create table pokus1 (a char(10));
insert into pokus1 values ('1234');
select *, length(a) from pokus1;
select * from pokus1 where a='1234';
select * from pokus1 where a='1234      ';
create table pokus2 (a varchar(10));
insert into pokus2 values ('1234');
select *, length(a) from pokus2;

--Porovnejte totéž v MySQL!