SQL-Abfrage konnte nicht durchgeführt werden!

select `A_V_ID` as `K_ID`, `A_URL` as `URL_REGEX` from `T_ANGEBOT` where `A_ID` = ;

Error:
SQLSTATE[42000]: Syntax error or access violation: 1064 You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near '' at line 2