How can I do an inner join inside of a subquery? MySQL - mysql

Question

I am trying to adapt this select statement to my tables. This query selects all of the zip codes from a zip code table that are within a certain distance of a given zip code. However, I have a Salon table that stores the zip codes as a foreign from the zip code table. I need to select all of the salons within a certain distance of the given zip code.
DELIMITER //
CREATE PROCEDURE zip_search(lat_param FLOAT(9,6),
long_param FLOAT(9,6), dist_param INT(100)
)
BEGIN
SELECT zipcode
FROM (
SELECT z.zipcode, z.latitude, z.longitude,
p.radius,
p.distance_unit
* DEGREES(ACOS(COS(RADIANS(p.latpoint))
* COS(RADIANS(z.latitude))
* COS(RADIANS(p.longpoint - z.longitude))
+ SIN(RADIANS(p.latpoint))
* SIN(RADIANS(z.latitude)))) AS distance
FROM accounts_zip AS z
JOIN ( /* these are the query parameters */
SELECT lat_param AS latpoint, long_param AS longpoint,
dist_param AS radius, 69.0 AS distance_unit
) AS p ON 1=1
WHERE z.latitude
BETWEEN p.latpoint - (p.radius / p.distance_unit)
AND p.latpoint + (p.radius / p.distance_unit)
AND z.longitude
BETWEEN p.longpoint - (p.radius / (p.distance_unit * COS(RADIANS(p.latpoint))))
AND p.longpoint + (p.radius / (p.distance_unit * COS(RADIANS(p.latpoint))))
) AS d
WHERE distance <= radius
ORDER BY distance;
END //
I tried adding an inner join after selecting from the salon table, however I do not understand sub queries and joins very well. Any thoughts would be greatly appreciated.
DELIMITER //
CREATE PROCEDURE zip_search(lat_param FLOAT(9,6),
long_param FLOAT(9,6), dist_param INT(100)
)
BEGIN
SELECT *
FROM (
SELECT z.zipcode, z.latitude, z.longitude,
p.radius,
p.distance_unit
* DEGREES(ACOS(COS(RADIANS(p.latpoint))
* COS(RADIANS(z.latitude))
* COS(RADIANS(p.longpoint - z.longitude))
+ SIN(RADIANS(p.latpoint))
* SIN(RADIANS(z.latitude)))) AS distance
FROM accounts_salon INNER JOIN accounts_zip ON accounts_salon.id=accounts_zip.id AS z
JOIN ( /* these are the query parameters */
SELECT lat_param AS latpoint, long_param AS longpoint,
dist_param AS radius, 69.0 AS distance_unit
) AS p ON 1=1
WHERE z.latitude
BETWEEN p.latpoint - (p.radius / p.distance_unit)
AND p.latpoint + (p.radius / p.distance_unit)
AND z.longitude
BETWEEN p.longpoint - (p.radius / (p.distance_unit * COS(RADIANS(p.latpoint))))
AND p.longpoint + (p.radius / (p.distance_unit * COS(RADIANS(p.latpoint))))
) AS d
WHERE distance <= radius
ORDER BY distance;
END //

Answer 1

I don't think the ' AS z' in first inner join is necessary, if you try to get the join result of tables accounts_salon and accounts_zip, and treat it as the left table of second inner join, then just continure write the next inner join.