PostgreSQL view embedded if-statements - postgresql

Question

In my database, for stores that have no rating from Reseller Ratings, they still have an entry but have -1.0 instead of a number between 0.0 and 10.0. The following query results in -10.00 showing up in my view for those stores with -1.0. Instead, I would like either nothing or a - showing up in its place, but I'm not very comfortable with implementing embedded if-statements in my view. Here is my current view.
CREATE VIEW myview AS
SELECT co_url_name AS company_url, score_combined AS stella_score, trunc(score*10, 2) AS bizrate_score,
(SELECT trunc("lifetimeRating"*10, 2)) AS resellerRating_score
FROM ss_profile_co AS s LEFT OUTER JOIN "resellerRatings_ratings" AS r
ON s.id = r.company_id
LEFT OUTER JOIN (SELECT * FROM bizrate_bizrate_ratings WHERE score_name = 'Overall rating') AS b
ON s.id = b.fk_co_id
ORDER BY co_url_name ASC;
The line (SELECT trunc("lifetimeRating"*10, 2)) AS resellerRating_score is the one that returns the negative numbers (or, for valid entries, will return a score between 0.00 and 100.00).
Obviously, I could simply remove these entries from the database that result in this, but it's half a learning experience and half out of my hands to do so anyways.
I appreciate the help!
EDIT: Attempted an embedded if but not surprisingly got an error.
IF (SELECT trunc("lifetimeRating"*10, 2)) = -10.00 THEN NULL ELSE (SELECT trunc("lifetimeRating"*10, 2)) AS resellerRating_score
EDIT2: Figured it out. Line in question is as follows:
(SELECT trunc("lifetimeRating"*10, 2) WHERE trunc("lifetimeRating"*10, 2) > 0) AS resellerrating_score
/foreveralone

Answer 1

Could look like this:
CREATE VIEW myview AS
SELECT co_url_name AS company_url
,score_combined AS stella_score
,trunc(score * 10, 2) AS bizrate_score
,CASE WHEN "lifetimeRating" < 0
THEN NULL
ELSE trunc("lifetimeRating" * 10, 2)
END AS resellerRating_score
FROM ss_profile_co s
LEFT JOIN "resellerRatings_ratings" r ON r.company_id = s.id
LEFT JOIN bizrate_bizrate_ratings b ON b.score_name = 'Overall rating'
AND b.fk_co_id = s.id
ORDER BY co_url_name;
Major points
Concerning your core question: the sub-select without a FROM clause serves no purpose. I simplified that and use a CASE statement instead.
I also simplified your LEFT JOIN to bizrate_bizrate_ratings. No sub-select necessary either. I pulled the WHERE clause up into the JOIN condition. Simpler and faster.
I would advise not to use mixed case identifiers, so you never have to use double quotes. (This probably makes #Daniels comment invalid, because lifetimerating != "lifetimeRating"