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#
# Try DENSE_RANK() function
#
create table t1 (
pk int primary key,
a int,
b int
);
insert into t1 values
( 1 , 0, 10),
( 2 , 0, 10),
( 3 , 1, 10),
( 4 , 1, 10),
( 8 , 2, 10),
( 5 , 2, 20),
( 6 , 2, 20),
( 7 , 2, 20),
( 9 , 4, 20),
(10 , 4, 20);
select a, rank() over (order by a) as rank,
dense_rank() over (order by a) as dense_rank
from t1;
a rank dense_rank
0 1 1
0 1 1
1 3 2
1 3 2
2 5 3
2 5 3
2 5 3
2 5 3
4 9 4
4 9 4
select a, b, rank() over (partition by b order by a) as rank,
dense_rank() over (partition by b order by a) as dense_rank
from t1;
a b rank dense_rank
0 10 1 1
0 10 1 1
1 10 3 2
1 10 3 2
2 10 5 3
2 20 1 1
2 20 1 1
2 20 1 1
4 20 4 2
4 20 4 2
drop table t1;
#
# Test with null values in the table.
#
create table t2 (s1 int, s2 char(5));
insert into t2 values (1,'a');
insert into t2 values (null,null);
insert into t2 values (1,null);
insert into t2 values (null,'a');
insert into t2 values (null,'c');
insert into t2 values (2,'b');
insert into t2 values (-1,'');
select *, rank() over (order by s1) as rank,
dense_rank() over (order by s1) as dense_rank
from t2
order by s1, s2;
s1 s2 rank dense_rank
NULL NULL 1 1
NULL a 1 1
NULL c 1 1
-1 4 2
1 NULL 5 3
1 a 5 3
2 b 7 4
select *, rank() over (partition by s2 order by s1) as rank,
dense_rank() over (partition by s2 order by s1) as dense_rank
from t2
order by s1, s2;
s1 s2 rank dense_rank
NULL NULL 1 1
NULL a 1 1
NULL c 1 1
-1 1 1
1 NULL 2 2
1 a 2 2
2 b 1 1
select *, rank() over (order by s2) as rank,
dense_rank() over (order by s2) as dense_rank
from t2
order by s2, s1;
s1 s2 rank dense_rank
NULL NULL 1 1
1 NULL 1 1
-1 3 2
NULL a 4 3
1 a 4 3
2 b 6 4
NULL c 7 5
select *, rank() over (partition by s1 order by s2) as rank,
dense_rank() over (partition by s1 order by s2) as dense_rank
from t2;
s1 s2 rank dense_rank
NULL NULL 1 1
NULL a 2 2
NULL c 3 3
-1 1 1
1 NULL 1 1
1 a 2 2
2 b 1 1
drop table t2;
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