anchor.diff:      : QUESTION_
       ;
   
  -number
  +numberLiterals
      : NUMBER_
      ;
   
  -string
  +stringLiterals
       : STRING_
       | characterSet_? STRING_ collateClause_?
       | IDENTIFIER_ STRING_ COLLATE (STRING_ | IDENTIFIER_)?
  
positive.code:     ;
  
  orderByItem
      : (columnName | number | expr) (ASC | DESC)?
      ;
  
  dataType
  
negative.code:     ;
  
  literals_
      : numberLiterals
      | stringLiterals
      | booleanLiterals
      | nullValueLiterals
      | bitValueLiterals
  