mysql中如何替代oracle中的EMPTY_BLOB（）

Java code

String sql = "insert into SSC_InsuranceCardMovement(oid,managedOrgId,cardFile) values(?,?,EMPTY_BLOB()) ";

PreparedStatement ps = conn.prepareStatement(sql);

执行会报 FUNCTION EMPTY_BLOB does not exist
mysql可有替代方法?还请各位帮帮忙!

------解决方案--------------------
String sql = "insert into SSC_InsuranceCardMovement(oid,managedOrgId,cardFile) values(?,?,NULL) ";