RANK

Description

The RANK() function is used to calculate the rank of the current row within a specified partition. The ranking starts from 1 and is sorted based on the values in the ORDER BY clause. If there are identical sorting values, the RANK() function assigns the same rank to these rows and skips the next rank.

Syntax

RANK() OVER ([PARTITION BY column_name | column_name, ...] [ORDER BY column_name [ASC|DESC], ...])

Parameter Description

• PARTITION BY: Optional parameter used to partition the data. You can specify one or more column names to partition the data.
• ORDER BY: Optional parameter used to specify the columns and the sorting order (ascending or descending).

Return Value

• The return value type is bigint.
• The return value may be non-continuous and may have duplicates. If there are identical ORDER BY values, the result is the same, representing the rank of the first ORDER BY row.

Example

1. Basic Usage We can use the RANK() function to calculate the salary rank of each employee.

   SELECT name, salary, RANK() OVER (ORDER BY salary DESC) AS rank FROM VALUES ('Eric', 1, 28000), ('Alex', 1, 32000), ('Felix', 2, 21000), ('Frank', 1, 30000), ('Tom', 2, 23000), ('Jane', 3, 29000), ('Jeff', 3, 35000), ('Paul', 2, 29000), ('Charles', 2, 23000), ('Charles F', 2, 23000), ('null',4,null), ('NotNull',4,23000) AS tab(name, dep_no, salary); +-----------+--------+------+ | name | salary | rank | +-----------+--------+------+ | Jeff | 35000 | 1 | | Alex | 32000 | 2 | | Frank | 30000 | 3 | | Jane | 29000 | 4 | | Paul | 29000 | 4 | | Eric | 28000 | 6 | | Tom | 23000 | 7 | | Charles | 23000 | 7 | | Charles F | 23000 | 7 | | NotNull | 23000 | 7 | | Felix | 21000 | 11 | | null | null | 12 | +-----------+--------+------+

2. Partition Usage If we want to calculate salary rankings based on employee grades, we can use the PARTITION BY clause.

   SELECT name,dep_no, salary, RANK() OVER (PARTITION BY dep_no ORDER BY salary DESC) AS rank FROM VALUES ('Eric', 1, 28000), ('Alex', 1, 32000), ('Felix', 2, 21000), ('Frank', 1, 30000), ('Tom', 2, 23000), ('Jane', 3, 29000), ('Jeff', 3, 35000), ('Paul', 2, 29000), ('Charles', 2, 23000), ('Charles F', 2, 23000), ('null',4,null), ('NotNull',4,23000) AS tab(name, dep_no, salary); +-----------+--------+--------+------+ | name | dep_no | salary | rank | +-----------+--------+--------+------+ | Jeff | 3 | 35000 | 1 | | Jane | 3 | 29000 | 2 | | Alex | 1 | 32000 | 1 | | Frank | 1 | 30000 | 2 | | Eric | 1 | 28000 | 3 | | Paul | 2 | 29000 | 1 | | Tom | 2 | 23000 | 2 | | Charles | 2 | 23000 | 2 | | Charles F | 2 | 23000 | 2 | | Felix | 2 | 21000 | 5 | | NotNull | 4 | 23000 | 1 | | null | 4 | null | 2 | +-----------+--------+--------+------+

3. Multi-column Sorting If we need to sort based on two or more columns, we can specify these columns in the ORDER BY clause.

   SELECT name,dep_no, salary, RANK() OVER (PARTITION BY dep_no ORDER BY salary DESC,name ASC) AS rank FROM VALUES ('Eric', 1, 28000), ('Alex', 1, 32000), ('Felix', 2, 21000), ('Frank', 1, 30000), ('Tom', 2, 23000), ('Jane', 3, 29000), ('Jeff', 3, 35000), ('Paul', 2, 29000), ('Charles', 2, 23000), ('Charles F', 2, 23000), ('null',4,null), ('NotNull',4,23000) AS tab(name, dep_no, salary); +-----------+--------+--------+------+ | name | dep_no | salary | rank | +-----------+--------+--------+------+ | Jeff | 3 | 35000 | 1 | | Jane | 3 | 29000 | 2 | | Alex | 1 | 32000 | 1 | | Frank | 1 | 30000 | 2 | | Eric | 1 | 28000 | 3 | | Paul | 2 | 29000 | 1 | | Charles | 2 | 23000 | 2 | | Charles F | 2 | 23000 | 3 | | Tom | 2 | 23000 | 4 | | Felix | 2 | 21000 | 5 | | NotNull | 4 | 23000 | 1 | | null | 4 | null | 2 | +-----------+--------+--------+------+

Notes

• The RANK() function may produce non-continuous rankings in the presence of identical sort values.
• When using the RANK() function, ensure that the columns in the ORDER BY clause match the columns you wish to rank by.