sqlite query performance using nested queries

I use the following sqlite query in c#. The query is iterated for 100K items. I feel the execution is slow and by optimizing the query the speed can be increased

insert into salesmetrics(salesid, salesrankcount, volumerankcount, countsales,Avgsales) select @salesid,sum(salesrank), sum(volumerank), Count(salesrank), avg(salesrank) from (select salesrank, volumerank from salesindex Join SalesData on salesindex.salesindexID = salesData.salesindexID where SourceID = @Sourceid and Content like @content group by salesindex.salesindexID)