distinct predicate fails with Mismatched types: varchar(1) vs varchar(32)

[the6campbells]

Presto server/jdbc 0.170

Mapped to MySQL

select rnum, tvchar.cvchar from mysql_cert.dbcert.tvchar where tvchar.cvchar is distinct from ' '

select rnum, tvchar.cvchar from mysql_cert.dbcert.tvchar where not ( tvchar.cvchar is not distinct from ' ')

Error: Query failed (#20170402_174600_04939_impt7): Mismatched types: varchar(1) vs varchar(32)
SQLState: null
ErrorCode: 65536

create table TVCHAR ( RNUM integer not null , CVCHAR varchar(32 ) null ) ;

insert into TVCHAR(RNUM, CVCHAR) values ( 0, NULL);
insert into TVCHAR(RNUM, CVCHAR) values ( 1, '');
insert into TVCHAR(RNUM, CVCHAR) values ( 2, ' ');
insert into TVCHAR(RNUM, CVCHAR) values ( 3, 'BB');
insert into TVCHAR(RNUM, CVCHAR) values ( 4, 'EE');
insert into TVCHAR(RNUM, CVCHAR) values ( 5, 'FF');

vs others which function including

select rnum, tvchar.cvchar from mysql_cert.dbcert.tvchar where tvchar.cvchar is not distinct from ' '

select rnum, tvchar.cvchar from mysql_cert.dbcert.tvchar where (tvchar.cvchar = ' ') or (tvchar.cvchar is null and ' ' is null)

[sopel39]

this indeed seems like a bug. Implicit cast should be used. FYI: @martint

[dqmdev]

same issue exists in recent (i.e 0.279+) versions of Presto.