ij version 10.8

ij> connect 'jdbc:derby://localhost:1527/challengedb;create=true';

ij> select * from app.user_count where datetime > {fn timestampdiff(SQL_TSI_SECOND, -30, CURRENT_TIMESTAMP)};
ERROR 42X45: INTEGER is an invalid type for argument number 2 of TIMESTAMPDIFF.
ij>