sql adding a new row to select query

[Manaralg]

how to add an average new row to a select query?
I have a select query that has 50 rows and I want to add a row on top of all rows named averages to calculate only 4 or the columns averages how do I do it?

[lovasoa]

Hello and welcome to SQLPage! This is a good sql question. This can be solved using a common table expression and an UNION:

WITH InitialQuery AS (
    -- Your complex query goes here
    SELECT column1, column2, column3
    FROM some_table
    WHERE some_condition
)

SELECT -- Return averages first
    AVG(column1) AS column1,
    AVG(column2) AS column2,
    AVG(column3) AS column3
FROM InitialQuery

UNION ALL -- Then return the full results

SELECT * FROM InitialQuery;