What does “select count(1) from table_name” on any database tables mean?

Question

When we execute select count(*) from table_name it returns the number of rows.

What does count(1) do? What does 1 signify here

Answer 1

This is similar to the difference between

SELECT * FROM table_name and SELECT 1 FROM table_name.  

If you do

SELECT 1 FROM table_name

it will give you the number 1 for each row in the table. So yes count(*) and count(1) will provide the same results as will count(8) or count(column_name)