How to optimize sqlite query?

Question

SQL

Hello
There is a request (sqlite .net). It takes an unacceptably long time (more than 30 seconds), although there is only one left join and it costs limit 0.1000. The amount of data is approximately 100,000 records in each of the tables. Can you suggest how to optimize it?

select
G.lemma as lemma,
G.id as id,
group_concat(distinct G.words) as words,
case when sum(K.some_data) is not null then sum(K.some_data) else 0 end as summ,
count(K.id) as cnt,
G.status as status,
G.stop_out as stop_out,
group_concat(K.id) as spl_id,
group_concat(K.keyword) as spl_kw,
group_concat(K.some_data) as spl_data,
group_concat(K.status) as spl_status
from [source_green_groups] G
left join [source_green_keywords] K on K.sg_id = G.id 
group by G.lemma
order by cnt desc
limit 0,1000

Thanks

Answer 1

Check for an index on the field
source_green_keywords.sg_id