postgis postgres计数和ST_Distance函数的按列分组

Question

This SQL produces the following:

SELECT city FROM travel_logs ORDER BY ST_Distance(travel_logs.start_point, ST_GeographyFromText('SRID=4326;POINT(101.652506 3.167610)')) 

"Tshopo"
"Tshopo"
"Mongala"
"Haut-Komo"

This SQL produces the following:

SELECT city, count(*) AS count FROM travel_logs GROUP BY travel_logs.start_point, city ORDER BY ST_Distance(travel_logs.start_point, ST_GeographyFromText('SRID=4326;POINT(101.652506 3.167610)')) 

"Tshopo";1
"Tshopo";1
"Mongala";1
"Haut-Komo";1

Basically, I want the result like this that groups by city and the number of times same city occurs. something like this

"Tshopo";2  <--- its summed up correctly
"Mongala";1
"Haut-Komo";1

Im not an expert on joins, subquery, would that help ? Thanks in advance.

Answer 1

this worked for me:

select city, count(*) as count
from
(SELECT city FROM travel_logs ORDER BY ST_Distance(travel_logs.start_point, ST_GeographyFromText('SRID=4326;POINT(101.652506 3.167610)'))
) as subquery_travel_logs_nearest group by city

Answer 2

Simple, plain SQL without a sub-query:

SELECT city, count(*)
FROM travel_logs
GROUP BY city
ORDER BY ST_Distance(start_point,
         ST_GeographyFromText('SRID=4326;POINT(101.652506 3.167610)'));