SELECT column but also add AVG column - mysql

Question

I'm not quite sure how to expand this query so that I can also have a AVG(price_current) column ... instead of having to calculate this value within PHP once the query comes back.
SELECT
listing_subtype, bedrooms, total_baths, tot_sqft_finished, price_current, latitude, longitude, (
3959 * acos (
cos ( radians(48.639) )
* cos( radians( latitude ) )
* cos( radians( longitude ) - radians(-123.404) )
+ sin ( radians(48.639) )
* sin( radians( latitude ) )
)
) AS distance
FROM rets_property_resi
WHERE listing_subtype = 'Single Family Detached' AND
bedrooms >= 2 AND bedrooms <= 3 AND
total_baths >= 1 AND total_baths <= 2 AND
tot_sqft_finished >= 2000 AND tot_sqft_finished <= 2500
HAVING distance < 5
ORDER BY distance
LIMIT 0, 25;

Answer 1

I'm going to make some assumptions here:
You look for similar houses/homes in a given radius around a requested one. Each of those homes has a primary key in the table you are querying from. Let us call that primKey here.
Additionally, you want the average price of all returned homes which is limited to 0,25, and not the AVG of all records in the table that match you WHERE clause.
All returned rows will have therefore an extra field with the average price and is the same for each row.
You will have to run the same query again as a subquery. However, since you want to limit the AVG you have to run that in a subquery to calculate the correct AVG.
This is really clunky:
SELECT
rets_property_resi.listing_subtype, rets_property_resi.bedrooms, rets_property_resi.total_baths, rets_property_resi.tot_sqft_finished, rets_property_resi.price_current, rets_property_resi.latitude, rets_property_resi.longitude, (
3959 * acos (
cos ( radians(48.639) )
* cos( radians( latitude ) )
* cos( radians( longitude ) - radians(-123.404) )
+ sin ( radians(48.639) )
* sin( radians( latitude ) )
)
) AS distance, outerSubQuery.averagePrice
FROM rets_property_resi
LEFT JOIN
(
SELECT innerSubQuery.primKey AS primKey, AVG(innerSubQuery.price_current) AS averagePrice
FROM
(SELECT
primKey, price_current, (
3959 * acos (
cos ( radians(48.639) )
* cos( radians( latitude ) )
* cos( radians( longitude ) - radians(-123.404) )
+ sin ( radians(48.639) )
* sin( radians( latitude ) )
)
) AS distance
FROM rets_property_resi
WHERE listing_subtype = 'Single Family Detached' AND
bedrooms >= 2 AND bedrooms <= 3 AND
total_baths >= 1 AND total_baths <= 2 AND
tot_sqft_finished >= 2000 AND tot_sqft_finished <= 2500
HAVING distance < 5
ORDER BY distance
LIMIT 0, 25) AS innerSubQuery
GROUP BY innerSubQuery.primKey
) AS outerSubQuery ON (outerSubQuery.primKey = rets_property_resi.primKey)
WHERE listing_subtype = 'Single Family Detached' AND
bedrooms >= 2 AND bedrooms <= 3 AND
total_baths >= 1 AND total_baths <= 2 AND
tot_sqft_finished >= 2000 AND tot_sqft_finished <= 2500
HAVING distance < 5
ORDER BY distance
LIMIT 0, 25;
I bet there is a more elegant version of this though. You might be better off with a temporary table here or keep just calculating in code.