The difference between rownumber and rank in sql

ROW_NUMBER and RANK are functions used to sort and number SQL result sets. ROW_NUMBER assigns consecutive integers to rows in insertion order, while RANK assigns the same rank to rows with the same value and renumbers subsequent rows to avoid duplication. ROW_NUMBER always returns consecutive integers, while RANK can return the same or different ranks, depending on the row's value. ROW_NUMBER is used to number rows in insertion order or to number contiguous subsets based on specific criteria, while RANK is used to rank rows or determine the relative position of rows with the same value.

The difference between ROW_NUMBER and RANK in SQL

ROW_NUMBER and RANK are both used in SQL to compare result sets Functions for sorting and numbering. While both serve a similar purpose, there are some key differences in their implementation and results.

Implementation Differences

• ROW_NUMBER: Assigns a unique integer to each row, numbered in the order in which the rows are inserted.
• RANK: Assign rows with the same value the same rank, but renumber subsequent rows to ensure there are no duplicate ranks.

Difference in results

• ROW_NUMBER: Always returns consecutive integers regardless of row values. All rows under the same rank will be assigned the same ROW_NUMBER.
• RANK: Can return the same or different rankings, depending on the row's value. All rows under the same rank will be assigned the same RANK.

Usage scenarios

• ROW_NUMBER: When rows need to be numbered in insertion order, or when rows need to be numbered based on a specific It is useful when consecutive subsets of conditions are numbered.
• RANK: It is useful when you need to rank rows, or when you need to determine the relative position of rows with the same value.

Example

-- ROW_NUMBER
SELECT ROW_NUMBER() OVER (ORDER BY id) AS RowNum, *
FROM table_name;

-- RANK
SELECT RANK() OVER (ORDER BY id) AS Rank, *
FROM table_name;

Result

##55 4

id	RowNum	Rank
1	1	1
2	2	1
3	3	3
4	4	2

The above is the detailed content of The difference between rownumber and rank in sql. For more information, please follow other related articles on the PHP Chinese website!