Describing a Categorical Series
Learn how to describe a categorical series using SQL.
We'll cover the following...
Overview
Categorical values are taken from a limited set of known values. Common examples are user, product, category, and so on.
To demonstrate, we are going to use the following list of values:
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SELECT * FROM (VALUES ('orange'), ('apple'), ('banana'), ('apple')) AS t(fruit);
Counting distinct values
To count the number of rows, we can use the COUNT
function as we did before:
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SELECTCOUNT(*)FROM (VALUES ('orange'), ('apple'), ('banana'), ('apple')) AS t(fruit);
Using COUNT(*)
, we found that the series has 4 rows. However, our series can have duplicate values. If we want to know how many unique values we have in the series, we can use the DISTINCT
...