Explain EXPLAIN SYNTAX (children 1)
 SelectWithUnionQuery (children 1)
  ExpressionList (children 1)
   SelectQuery (children 3)
    ExpressionList (children 2)
     Identifier msg
     Function toDateTime (alias time) (children 1)
      ExpressionList (children 1)
       Function intDiv (children 1)
        ExpressionList (children 2)
         Identifier ms
         Literal UInt64_1000
    TablesInSelectQuery (children 1)
     TablesInSelectQueryElement (children 1)
      TableExpression (children 1)
       Subquery (children 1)
        SelectWithUnionQuery (children 1)
         ExpressionList (children 1)
          SelectQuery (children 3)
           ExpressionList (children 2)
            Literal \'hello\' (alias msg)
            Function multiply (alias ms) (children 1)
             ExpressionList (children 2)
              Function toUInt64 (children 1)
               ExpressionList (children 1)
                Identifier t
              Literal UInt64_1000
           TablesInSelectQuery (children 1)
            TablesInSelectQueryElement (children 1)
             TableExpression (children 1)
              Function generateRandom (children 1)
               ExpressionList (children 1)
                Literal \'t DateTime\'
           Literal UInt64_10
    ExpressionList (children 2)
     OrderByElement (children 1)
      Identifier msg
     OrderByElement (children 1)
      Identifier time
