(you don't have to strictly follow this form)

ClickHouse fails when String and LowCardinality(String) columns are connected with UNION ALL. Steps to reproduce:

create temporary table t1(a String);

create temporary table t2(a LowCardinality(String));

select a from t1 union all select a from t2;

Received exception from server (version 19.1.6):
Code: 386. DB::Exception: Received from localhost:9000, ::1. DB::Exception: There is no supertype for types String, LowCardinality(String) because some of them are String/FixedString and some of them are not.