HTTP ERROR 500

Trying to render page /index/, SQL:execute_helper(sessions/delete_old) - Error: ERROR: syntax error at or near "$1" LINE 2: where date_exp>now() - interval $1||' days'; ^ , bind='1' query: delete from Tuser_sessions where date_exp>now() - interval $1||' days';

"SQL:execute_helper(sessions/delete_old) - Error: ERROR:  syntax error at or near "$1"
LINE 2: where date_exp>now() - interval $1||' days';
                                        ^
,
bind='1'
query:
delete from Tuser_sessions
where date_exp>now() - interval $1||' days';

"