PostgreSQL Views: Referencing one calculated field in another calculated field

Question

I have the same question as #1895500, but with PostgreSQL not MySQL.

How can I define a view that has a calculated field, for example:

 (mytable.col1 * 2) AS times_two

... and create another calculated field that's based on the first one:

 (times_two * 2) AS times_four

...?

Answer 1

Depending on how heavy the formla is, you could use a subquery:

select inner.*, times_two * 2 from
(select mycol * 2 as times_two from table) sub

Or rewrite the computation:

select mycol * 2, mycol * 2 * 2 from table