SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 2)
   ExpressionList (children 1)
    Function count (children 1)
     ExpressionList
   TablesInSelectQuery (children 2)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      TableIdentifier customer
    TablesInSelectQueryElement (children 2)
     TableExpression (children 1)
      TableIdentifier nation
     TableJoin (children 1)
      Function equals (children 1)
       ExpressionList (children 2)
        Identifier c_nationkey
        Identifier n_nationkey
