How to use oracle rank function

The Oracle RANK() function ranks the dataset through the specified sort field and assigns rankings starting from 1. Usage example: sql SELECT employee_id, name, salary, RANK() OVER (ORDER BY salary ASC) AS salary_rank FROM employees;

Use of Oracle RANK() function

The RANK() function is an analysis function in Oracle that ranks a set of rows. Ranking starts at 1 and is assigned according to the ascending or descending order of the specified sorting criteria.

grammar:

 <code>RANK() OVER ( [PARTITION BY 分区子句] ORDER BY 排序字段[ASC|DESC] )</code>

parameter:

• PARTITION BY Partition clause: Optional, divide the data set into different groups, and rank each group separately.
• ORDER BY Sort Field: The sort field used to determine the ranking.
• ASC|DESC: Optional, specify whether to rank ascending or descending (default ascending).

usage:

The RANK() function is often used in conjunction with other analytical functions such as ROW_NUMBER() or DENSE_RANK() to provide flexible ranking options.

Example:

The following example ranks employees in the "employees" table in ascending order in the "salary" field:

 <code>SELECT employee_id, name, salary, RANK() OVER (ORDER BY salary ASC) AS salary_rank FROM employees;</code>

The results will show the employee ID, name, salary, and salary ranking for each employee.

Notice:

• The RANK() function assigns the same ranking to repeated values.
• If the PARTITION BY clause is not specified, the entire dataset is ranked.
• If the ORDER BY clause is not specified, it is ranked in the default sort order of the table.
• The RANK() function performs special processing on NULL values, placing them as last.

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