SQL - Calculate Rank

SQL > Advanced SQL > Rank

Displaying the rank associated with each row is a common request. Some databases (such as SQL Server and Oracle) provide a RANK function that can easily achieve this, though this is not true for all databases (for example, MySQL does not have a RANK function). In this section, we discuss how we can show the ranking in the absence of such a function.

The general idea to display rank in SQL is to do a self-join, then list out the results in order, and finally do a count on the number of records that's listed ahead of (and including) the record of interest. Let's use an example to illustrate. Say we have the following table,

Table Total_Sales

Name	Sales
John	10
Jennifer	15
Stella	20
Sophia	40
Greg	50
Jeff	20

we would type,

SELECT a1.Name, a1.Sales, COUNT (a2.Sales) Sales_Rank
FROM Total_Sales a1, Total_Sales a2
WHERE a1.Sales < a2.Sales OR (a1.Sales=a2.Sales AND a1.Name = a2.Name)
GROUP BY a1.Name, a1.Sales
ORDER BY a1.Sales DESC, a1.Name DESC;

Result:

Name	Sales	Sales_Rank
Greg	50	1
Sophia	40	2
Stella	20	3
Jeff	20	3
Jennifer	15	5
John	10	6

Please note that in this case, there WHERE clause accounts for the possibility that multiple rows of data have the same value of in the Sales column. If we know for sure that there are no duplicate values in the Sales column, we can change the WHERE clause to:

WHERE a1.Sales <= a2.Sales

List of SQL Complex Operations

Operation	Description
Rank	Calculates the ranking of a series of numbers
Median	Calculates the median of a series of numbers
Running Totals	Calculates the running total for a series of numbers
Percent To Total	Calculates the percent to total for each number in a series
Cumulative Percent To Total	Calculates the cumulative percent to total for each number in a series

Next: SQL Median

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SQL Rank

List of SQL Complex Operations