DROP MASK RULE

DropEncryptRule ::=
  'DROP' 'MASK' 'RULE' ifExists? maskRuleName (',' maskRuleName)*

ifExists ::=
  'IF' 'EXISTS'

maskRuleName ::=
  identifier

DROP MASK RULE t_mask, t_mask_1;

DROP MASK RULE IF EXISTS t_mask, t_mask_1;