SQLite：group_concat 似乎只拉第一行？

Question

I have a base query which functions as desired, and tells me which people have how many items for thing 'a':

SELECT Person || ' ' || COUNT(ResponsibleThing) FROM table WHERE thing='a' GROUP BY Person;

Person || ' ' || COUNT(ResponsibleThing)
-----------------------------------------------
Joe     340
Chris   34
Dave    612
Fred    272

What I really want is to collapse this result set into a CSV so that I can pivot on another column, with a result set that looks something like:

thing Person || '   ' || COUNT(ResponsibleThing)
----- -----------------------------------------
a     Joe     340,Chris     34,Dave     612,Fred    272
b     Chris     100, Frank     34

It seemed like group_concat would be the way to go, but strangely, I'm only getting back the first entry when I try to adapt the above query: SELECT group_concat((SELECT Person || ' ' || COUNT(ResponsibleThing) FROM table WHERE thing='a' GROUP BY Person));

group_concat((SELECT Person || '  ' || COUNT(ResponsibleThing) FROM table WHERE thing='a' GROUP BY Person))
----------------------------------------------------------------------------------------------------
Joe     340

Any ideas on how to get the full result set to be concatenated? Many thanks.

Answer 1

You need two levels of aggregation: first by person (that's your existing query), then overall:

select group_concat(res) res
from (
    select person || ' ' || count(*) res
    from mytable
    where thing = 'a'
    group by person
) t