"INTERVAL N <unit>" is now handled as an expression in itself and
as asuch will cause both statements such as
"SELECT '2008-12-31 23:59:59' + INTERVAL 1 SECOND;"
and
"select id from db2.t1 where DATE_ADD("2017-06-15", INTERVAL 10 DAY) < "2017-06-15";"
to be handled correctly. The compare test program contains some
heuristic checking, as the the embedded parser will in all cases
report date manipulation as the use of the add_date_interval()
function.