Explain EXPLAIN SYNTAX (children 1)
 SelectWithUnionQuery (children 1)
  ExpressionList (children 1)
   SelectQuery (children 2)
    ExpressionList (children 1)
     Function plus (children 1)
      ExpressionList (children 2)
       Function isNotNull (children 1)
        ExpressionList (children 1)
         Literal UInt64_1
       Function isNotNull (children 1)
        ExpressionList (children 1)
         Literal UInt64_2
    TablesInSelectQuery (children 1)
     TablesInSelectQueryElement (children 1)
      TableExpression (children 1)
       Function remote (children 1)
        ExpressionList (children 2)
         Literal \'127.2\'
         Identifier system.one
