Investments in 2016 SQL MySQL Leetcode Solution with SELECT CONCAT

Finding Total Investment Value (2016) for Policyholders with Matching Investments in Different Locations
This script calculates the sum of total investment values (tiv_2016) for policyholders in 2016 who:

Share the same tiv_2015 value with at least one other policyholder.
Reside in unique locations (distinct latitude and longitude combinations).
Input:

A table named "Insurance" with the following columns:

pid (int): Unique policy ID (primary key)
tiv_2015 (float): Total investment value in 2015
tiv_2016 (float): Total investment value in 2016
lat (float): Policyholder's city latitude (guaranteed not null)
lon (float): Policyholder's city longitude (guaranteed not null)
Output:

A table with one column named "tiv_2016" containing the rounded sum (to two decimal places) of tiv_2016 values meeting the criteria.

The given SQL query performs a series of operations on an Insurance table. Here's a step-by-step explanation:

Main Query:

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SELECT sum(tiv_2016) tiv_2016
FROM
Insurance
WHERE tiv_2015 IN
(SELECT tiv_2015 FROM Insurance GROUP BY tiv_2015 HAVING count(*)>1) AND
CONCAT(LAT, LON) IN (SELECT CONCAT(LAT, LON) FROM Insurance GROUP BY LAT, LON HAVING COUNT(*) = 1);
Objective:
The query aims to compute the sum of tiv_2016 values for certain insurance records based on specific conditions.

Conditions:

The tiv_2015 value of the records must be present in a subset of records where tiv_2015 is not unique (appears more than once).
The combination of LAT (latitude) and LON (longitude) values of the records must be unique (appear only once).
Breakdown:
Main Query:
SELECT sum(tiv_2016) tiv_2016:
This part of the query selects the sum of the tiv_2016 column values and gives it an alias tiv_2016.

FROM Insurance:
The data is being queried from the Insurance table.

WHERE tiv_2015 IN (...) AND CONCAT(LAT, LON) IN (...):
The WHERE clause filters the rows based on two conditions:

First Condition:
tiv_2015 IN:
This checks if the tiv_2015 value of a row is in the list of tiv_2015 values returned by the subquery:
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(SELECT tiv_2015 FROM Insurance GROUP BY tiv_2015 HAVING count(*)>1)
This subquery groups the Insurance table by tiv_2015 and returns those tiv_2015 values which have more than one record (HAVING count(*)>1).
Second Condition:
CONCAT(LAT, LON) IN:
This checks if the concatenated string of LAT and LON values of a row is in the list of concatenated LAT and LON values returned by another subquery:
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(SELECT CONCAT(LAT, LON) FROM Insurance GROUP BY LAT, LON HAVING COUNT(*) = 1)
This subquery groups the Insurance table by LAT and LON and returns those concatenated LAT and LON values which appear exactly once (HAVING COUNT(*) = 1).
Summary:
The query filters the records from the Insurance table where:

The tiv_2015 value appears in multiple rows.
The combination of LAT and LON values appears in exactly one row.
Finally, it computes the sum of the tiv_2016 values for these filtered records and returns this sum as tiv_2016.