Get columns of data with two different date range - sql

Question

I would like to get the average rating for last 7 days and last 14 days.
I tried using WITH AS to get the data but it's taking way too long to load. Any other way that is better and could reduce the run time?
syntax:
WITH last_7_days AS (
SELECT item, rating
FROM sales
WHERE (
rating IS NOT NULL
AND (entry_date >= CAST((CAST(now() AS timestamp) + (INTERVAL '-7 day')) AS date) AND entry_date < CAST((CAST(now() AS timestamp) + (INTERVAL '1 day')) AS date))
)
),
last_14_days AS (
SELECT item, rating
FROM sales
WHERE (
rating IS NOT NULL
AND (entry_date >= CAST((CAST(now() AS timestamp) + (INTERVAL '-14 day')) AS date) AND entry_date < CAST((CAST(now() AS timestamp) + (INTERVAL '1 day')) AS date))
)
)
SELECT last_7_days.item, avg(last_7_days.score) as "avg_last_7_days", avg(last_14_days.rating) as "avg_last_14_days", count(*) AS "count"
FROM last_7_days, last_14_days
WHERE last_7_days.item = last_14_days.item
GROUP BY last_7_days.item
ORDER BY "avg_last_7_days" DESC, last_7_days.item ASC
Result should be something like this:
item|avg_last_7_days|avg_last_14_days|count|
thank you

Answer 1

Use conditional aggregation:
SELECT item,
AVG(rating) FILTER (WHERE entry_date >= NOW() + interval '-7 day' AND entry_date < NOW() + interval '1 day') AS avg_rating_last_seven_days,
AVG(rating) FILTER (WHERE entry_date >= NOW() + interval '-14 day' AND entry_date < NOW() + interval '1 day') AS avg_rating_last_fourteen_days
FROM sales
WHERE rating IS NOT NULL AND
(entry_date >= NOW() + interval '-14 day' AND entry_date < NOW() + interval '1 day')
GROUP BY item;
Note: If you only care about the date, then perhaps you should use CURRENT_DATE or even NOW()::date.

Answer 2

Getting rid of all the casts and aggregating directly on the CTEs should help, try with the following:
WITH last_7_days AS (
SELECT
item,
AVG(rating) AS avg_rating_last_seven_days
FROM
sales
WHERE
rating IS NOT NULL AND
(entry_date >= NOW() + interval '-7 day' AND entry_date < NOW() + interval '1 day')
GROUP BY
1
),
last_14_days AS (
SELECT
item,
AVG(rating) AS avg_rating_last_fourteen_days
FROM
sales
WHERE
rating IS NOT NULL AND
(entry_date >= NOW() + interval '-14 day' AND entry_date < NOW() + interval '1 day')
GROUP BY
1
)
SELECT
lsd.item,
avg_rating_last_seven_days,
avg_rating_last_fourteen_days
FROM
last_7_days AS lsd
INNER JOIN
last_14_days AS lfd ON lsd.item = lfd.item
Let me know in case it helped on improving your current performance!