SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 3)
   ExpressionList (children 1)
    Asterisk
   TablesInSelectQuery (children 1)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      TableIdentifier dm_metric_small2
   Function and (children 1)
    ExpressionList (children 3)
     Function equals (children 1)
      ExpressionList (children 2)
       Identifier x
       Literal UInt64_1
     Function equals (children 1)
      ExpressionList (children 2)
       Identifier y
       Literal UInt64_1
     Function isNull (children 1)
      ExpressionList (children 1)
       Identifier z
