Column Aliases

Column Aliases

  • A column alias provides a way to create a clean or more descriptive header for a results set.
  • A column alias cannot be used in a SELECT, WHERE, GROUP BY or HAVING clause due to the order of execution. You must refer to the original column name.

In the previous example, we created a new column that was a calculated value. The problem is that the column header is now population / SurfaceArea. However, we can rename the column header to something cleaner by creating a column alias.  Look at the code snippet below.


SELECT name, population / SurfaceArea
     AS “People per square mile”
FROM country;

We used the AS keyword then in quotes we put the new column alias of “People per square mile.” Which changes the column header as seen show below.



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