Unable to perform query:

SELECT SQL_CALC_FOUND_ROWS `oldhamgalleryID`,`Ref_No_increment`,`Object_Type`,`Title`,`Date_Period`,`Associated_Place`,`Artist_Maker`,`Further_Information`,`Copyright_checkbox`,`Cost`,`Owner`,`Format`,`Donor`,`Collection`,`Sub_Set`,`Hide_Record_checkbox`,`Keywords`,`DateAmended`,`DateAmendedBy`,`DateCreated`,`DateCreatedBy` FROM `oldhamgallery` WHERE (( `Ref_No_increment` RLIKE '(^|')) LIMIT 0, 10

mysql error:Got error 'empty (sub)expression' from regexp