drop table if exists t1;
create table t1 (a int check (a>0));
insert into t1 values (1);
insert into t1 values (0);
drop table t1;
create table t1 (a int ,b int, check a>b);
insert into t1 values (1,0);
insert into t1 values (0,1);
drop table t1;
create table t1 (a int ,b int, constraint abc check (a>b));
insert into t1 values (1,0);
insert into t1 values (0,1);
drop table t1;
create table t1 (a int null);
insert into t1 values (1),(NULL);
drop table t1;