Learn SQL Database Programming

Detecting rare and outlier values

Detecting rare and outlier values can help you determine if you have bad or irrelevant data. The terms rare and outlier can be subjective. Different people might define rare and outlier data standards differently. Knowing this can help you prepare for possible disagreements in a business situation.

To see the distinct values in a table, execute the following query:

USE lahmansbaseballdb; SELECT DISTINCT h as hits, COUNT(h) as countFROM battingGROUP BY hitsORDER BY count;

The preceding query will give you a list of each distinct value in the h (hits) column and a count of those hits, as shown in the following two screenshots. This first screenshot shows you the beginning rows of the results:

This second ...