InsertQuery   (children 3)
 Identifier testnull
 ExpressionList (children 2)
  Identifier b
  Identifier c
 SelectWithUnionQuery (children 1)
  ExpressionList (children 1)
   SelectQuery (children 2)
    ExpressionList (children 2)
     Function toString (alias b) (children 1)
      ExpressionList (children 1)
       Function rand64 (children 1)
        ExpressionList
     Function toString (alias c) (children 1)
      ExpressionList (children 1)
       Function rand64 (children 1)
        ExpressionList
    TablesInSelectQuery (children 1)
     TablesInSelectQueryElement (children 1)
      TableExpression (children 1)
       Function numbers (children 1)
        ExpressionList (children 1)
         Literal UInt64_1000000
