Reference alias in WHERE clause

Question

In psql, trying to reference alias in WHERE clause:

SELECT
    SUBSTRING(pk, 6, 2)::INT AS _year
FROM
    listing
WHERE
    _year > 90
         


        

Answer 1

Try this way

select * from (SELECT
    SUBSTRING(pk, 6, 2)::INT AS _year
FROM
    listing) a where _year>90