DROP TABLE IF EXISTS nulls;
set allow_deprecated_syntax_for_merge_tree=1;
CREATE TABLE nulls (d Date, x Nullable(UInt64)) ENGINE = MergeTree(d, d, 8192);
INSERT INTO nulls SELECT toDate('2000-01-01'), number % 10 != 0 ? number : NULL FROM system.numbers LIMIT 10000;
SELECT count() FROM nulls WHERE x IS NULL;
DROP TABLE nulls;