[Bug]: parse error in sql has `interval`

[Ifffff]

Describe the bug
sql:

select site as idc, sum(if(sm_name='ups1', 1, 0)) as countups1, sum(if(sm_name='s9', 1, 0)) as counts9, sum(if(sm_name='c7', 1, 0)) as countc7 from ocp_resource
        where used_flag='f' or (used_flag='m' and update_time >= date_add(now(), interval - 300 second)) group by site

SyntaxError: The current version does not support this SQL 81 (interval)