How to get the row number when using alias in orderby - sql

Question

I have a query. I use an alias in order by when using row_number and I got
[42703] ERROR: column "total_comments" does not exist error Position: 335
How can I fix this?
select
cr_seller_history_id,
c.created_at,
company_name,
business_name,
brand,
kep_mail,
address,
phone,
mail,
slug,
name,
point,
contact_positive,
contact_negative,
product_number,
(product_positive + product_negative) as total_comments,
ROW_NUMBER() OVER(ORDER BY total_comments) as rank
from cr_companies a
INNER JOIN cr_sellers b ON a.cr_company_id = b.cr_company_id
INNER JOIN cr_seller_histories c ON b.cr_seller_id = c.cr_seller_id
WHERE DATE(c.created_at) = DATE 'yesterday'
ORDER BY total_comments DESC NULLS LAST

Answer 1

The other solutions are a subquery, CTE, or a lateral join. So, you can write:
select . . .
v.total_comments,
row_number() over (order by v.total_comments) as rank
from cr_companies c join
cr_sellers s
on c.cr_company_id = s.cr_company_id join
cr_seller_histories sh
on s.cr_seller_id = sh.cr_seller_id, lateral
(values (product_positive + product_negative)) v(total_comments)
where DATE(c.created_at) = date 'yesterday'
order by v.total_comments desc nulls last;
Notice that I also changed the table aliases to be abbreviations for the table names. This is a best practice and makes it much easier to write, read, and modify queries.

Answer 2

the problem is in:
ROW_NUMBER() OVER(ORDER BY total_comments) as rank
you can't use alias like this - order by accepts alias in select, not in window function:
https://www.postgresql.org/docs/current/static/sql-select.html#SQL-SELECT-LIST
An output column's name can be used to refer to the column's value in
ORDER BY and GROUP BY clauses, but not in the WHERE or HAVING clauses;
there you must write out the expression instead.
instead try:
ROW_NUMBER() OVER(ORDER BY (product_positive + product_negative)) as rank
or use subquery - then alias can be used in window function