Explain EXPLAIN (children 2)
 Set
 SelectWithUnionQuery (children 1)
  ExpressionList (children 1)
   SelectQuery (children 5)
    ExpressionList (children 1)
     Function toDate (alias s) (children 1)
      ExpressionList (children 1)
       Identifier timestamp
    TablesInSelectQuery (children 1)
     TablesInSelectQueryElement (children 1)
      TableExpression (children 1)
       TableIdentifier test_table
    ExpressionList (children 1)
     OrderByElement (children 1)
      Function toDate (children 1)
       ExpressionList (children 1)
        Identifier timestamp
    Literal UInt64_1
    Set