drop table if exists t; create table t (a Int, b Int) engine = MergeTree order by (a, b) settings index_granularity = 400; insert into t select 0, 0 from numbers(50); insert into t select 0, 1 from numbers(350); insert into t select 1, 2 from numbers(400); insert into t select 2, 2 from numbers(400); insert into t select 3, 0 from numbers(100); select sleep(1) format Null; -- sleep a bit to wait possible merges after insert set max_threads = 1; optimize table t final; select sum(a) from t where a in (0, 3) and b = 0;