# PERCENT_RANK

Ranking function. Returns the percent rank of the current row within the partition as specified by the order by clause. The result is calculated with the following formula: `(rank - 1)/(total_rows - 1)`

# Syntax

``````PERCENT_RANK () OVER (
[PARTITION BY (col | expr), ...]
[ORDER BY (col | expr), ...]
)
``````

# Return Type

A `DOUBLE` data type.

# Examples

``````memsql> create table example (a int, b int);

memsql> insert into example values(1,2),(2,2),(3,3),(4,3);

memsql> select a,b, percent_rank() over(order by a,b) from example;
+------+------+-----------------------------------+
| a    | b    | percent_rank() over(order by a,b) |
+------+------+-----------------------------------+
|    1 |    2 |                                 0 |
|    2 |    2 |                0.3333333333333333 |
|    3 |    3 |                0.6666666666666666 |
|    4 |    3 |                                 1 |
+------+------+-----------------------------------+

memsql> select a,b, percent_rank() over(order by b) from example;
+------+------+---------------------------------+
| a    | b    | percent_rank() over(order by b) |
+------+------+---------------------------------+
|    1 |    2 |                               0 |
|    2 |    2 |                               0 |
|    3 |    3 |              0.6666666666666666 |
|    4 |    3 |              0.6666666666666666 |
+------+------+---------------------------------+
``````