# PERCENT_RANK

## Syntax

```PERCENT_RANK() OVER (
[ PARTITION BY partition_expression ]
[ ORDER BY order_list ]
)
```

## Description

PERCENT_RANK() is a window function that returns the relative percent rank of a given row. The following formula is used to calculate the percent rank:

```(rank - 1) / (number of rows in the window or partition - 1)
```

## Examples

```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 pk, a, b,
rank() over (order by a) as rank,
percent_rank() over (order by a) as pct_rank,
cume_dist() over (order by a) as cume_dist
from t1;
+----+------+------+------+--------------+--------------+
| pk | a    | b    | rank | pct_rank     | cume_dist    |
+----+------+------+------+--------------+--------------+
|  1 |    0 |   10 |    1 | 0.0000000000 | 0.2000000000 |
|  2 |    0 |   10 |    1 | 0.0000000000 | 0.2000000000 |
|  3 |    1 |   10 |    3 | 0.2222222222 | 0.4000000000 |
|  4 |    1 |   10 |    3 | 0.2222222222 | 0.4000000000 |
|  5 |    2 |   20 |    5 | 0.4444444444 | 0.8000000000 |
|  6 |    2 |   20 |    5 | 0.4444444444 | 0.8000000000 |
|  7 |    2 |   20 |    5 | 0.4444444444 | 0.8000000000 |
|  8 |    2 |   10 |    5 | 0.4444444444 | 0.8000000000 |
|  9 |    4 |   20 |    9 | 0.8888888889 | 1.0000000000 |
| 10 |    4 |   20 |    9 | 0.8888888889 | 1.0000000000 |
+----+------+------+------+--------------+--------------+

select pk, a, b,
percent_rank() over (order by pk) as pct_rank,
cume_dist() over (order by pk) as cume_dist
from t1 order by pk;
+----+------+------+--------------+--------------+
| pk | a    | b    | pct_rank     | cume_dist    |
+----+------+------+--------------+--------------+
|  1 |    0 |   10 | 0.0000000000 | 0.1000000000 |
|  2 |    0 |   10 | 0.1111111111 | 0.2000000000 |
|  3 |    1 |   10 | 0.2222222222 | 0.3000000000 |
|  4 |    1 |   10 | 0.3333333333 | 0.4000000000 |
|  5 |    2 |   20 | 0.4444444444 | 0.5000000000 |
|  6 |    2 |   20 | 0.5555555556 | 0.6000000000 |
|  7 |    2 |   20 | 0.6666666667 | 0.7000000000 |
|  8 |    2 |   10 | 0.7777777778 | 0.8000000000 |
|  9 |    4 |   20 | 0.8888888889 | 0.9000000000 |
| 10 |    4 |   20 | 1.0000000000 | 1.0000000000 |
+----+------+------+--------------+--------------+

select pk, a, b,
percent_rank() over (partition by a order by a) as pct_rank,
cume_dist() over (partition by a order by a) as cume_dist
from t1;
+----+------+------+--------------+--------------+
| pk | a    | b    | pct_rank     | cume_dist    |
+----+------+------+--------------+--------------+
|  1 |    0 |   10 | 0.0000000000 | 1.0000000000 |
|  2 |    0 |   10 | 0.0000000000 | 1.0000000000 |
|  3 |    1 |   10 | 0.0000000000 | 1.0000000000 |
|  4 |    1 |   10 | 0.0000000000 | 1.0000000000 |
|  5 |    2 |   20 | 0.0000000000 | 1.0000000000 |
|  6 |    2 |   20 | 0.0000000000 | 1.0000000000 |
|  7 |    2 |   20 | 0.0000000000 | 1.0000000000 |
|  8 |    2 |   10 | 0.0000000000 | 1.0000000000 |
|  9 |    4 |   20 | 0.0000000000 | 1.0000000000 |
| 10 |    4 |   20 | 0.0000000000 | 1.0000000000 |
+----+------+------+--------------+--------------+

```