anchor.diff:  DAY: 'DAY';
   DEALLOCATE: 'DEALLOCATE';
   DEFAULT: 'DEFAULT';
  +DEFINE: 'DEFINE';
   DEFINER: 'DEFINER';
   DELETE: 'DELETE';
   DENY: 'DENY';
   DESC: 'DESC';
   DESCRIBE: 'DESCRIBE';
   DESCRIPTOR: 'DESCRIPTOR';
  -DEFINE: 'DEFINE';
   DISTINCT: 'DISTINCT';
   DISTRIBUTED: 'DISTRIBUTED';
   DOUBLE: 'DOUBLE';
  
positive.code:     : ABSENT | ADD | ADMIN | AFTER | ALL | ANALYZE | ANY | ARRAY | ASC | AT | AUTHORIZATION
      | BERNOULLI | BOTH
      | CALL | CASCADE | CATALOGS | COLUMN | COLUMNS | COMMENT | COMMIT | COMMITTED | CONDITIONAL | COPARTITION | COUNT | CURRENT
      | DATA | DATE | DAY | DEFAULT | DEFINE | DEFINER | DESC | DESCRIPTOR | DISTRIBUTED | DOUBLE
      | EMPTY | ENCODING | ERROR | EXCLUDING | EXPLAIN
      | FETCH | FILTER | FINAL | FIRST | FOLLOWING | FORMAT | FUNCTIONS
      | GRANT | DENY | GRANTED | GRANTS | GRAPHVIZ | GROUPS
      | HOUR
      | IF | IGNORE | INCLUDING | INITIAL | INPUT | INTERVAL | INVOKER | IO | ISOLATION
      | JSON
  
negative.code: NULLIF: 'NULLIF';
  NULLS: 'NULLS';
  OBJECT: 'OBJECT';
  OF: 'OF';
  OFFSET: 'OFFSET';
  OMIT: 'OMIT';
  ON: 'ON';
  ONE: 'ONE';
  ONLY: 'ONLY';
  