anchor.diff:      : (UNIQUE | FULLTEXT | SPATIAL)?
       ;
   
  -alterClause_
  +alterDefinitionClause_
       : alterSpecification_ (COMMA_ alterSpecification_)*
       ;
   
  
positive.code:     ;
  
  alterTable
      : ALTER TABLE tableName alterClause_?
      ;
  
  dropTable
      : DROP TEMPORARY? TABLE (IF EXISTS)? tableName (COMMA_ tableName)*
      ;
  
  dropIndex
  
negative.code: subpartitionDefinition_
      : SUBPARTITION identifier_ partitionDefinitionOption_*
      ;
  
  dropTableSpecification_
      : TEMPORARY?
      ;
  
  tableExistClause_
      : (IF EXISTS)?
      ;