CreateQuery auto_assign_enum3 (children 3)
 Identifier auto_assign_enum3
 Columns definition (children 1)
  ExpressionList (children 1)
   ColumnDeclaration x (children 1)
    DataType enum (children 1)
     ExpressionList (children 3)
      Literal \'a\'
      Literal \'b\'
      Literal NULL
 Storage definition (children 2)
  Function MergeTree (children 1)
   ExpressionList
  Identifier x