DROP TABLE IF EXISTS t1__fuzz_13; DROP TABLE IF EXISTS t2__fuzz_47; SET allow_suspicious_low_cardinality_types = 1; CREATE TABLE t1__fuzz_13 (id Nullable(Int16)) ENGINE = MergeTree() ORDER BY id SETTINGS allow_nullable_key = 1; CREATE TABLE t2__fuzz_47 (id LowCardinality(Int16)) ENGINE = MergeTree() ORDER BY id; INSERT INTO t1__fuzz_13 VALUES (1); INSERT INTO t2__fuzz_47 VALUES (1); SELECT * FROM t1__fuzz_13 FULL OUTER JOIN t2__fuzz_47 ON 1 = 2;