clickhouse-client -q 'create table typed_nulls( str Nullable(String) ) Engine=Log'

clickhouse-client --param_n='\N' --query='insert into typed_nulls(str) values ( {n:Nullable(String)} )' --format=Vertical
Code: 456. DB::Exception: Query parameter `n` was not set

clickhouse-client --param_n='aa' --query='insert into typed_nulls(str) values ( {n:Nullable(String)} )' --format=Vertical
Code: 456. DB::Exception: Query parameter `n` was not set