SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 3)
   ExpressionList (children 1)
    Function or (children 1)
     ExpressionList (children 2)
      Function equals (children 1)
       ExpressionList (children 2)
        Identifier k
        Literal NULL
      Function equals (children 1)
       ExpressionList (children 2)
        Identifier k
        Literal UInt64_1000
   TablesInSelectQuery (children 1)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      TableIdentifier t_sparse_pk
   Literal UInt64_3