SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 2)
   ExpressionList (children 1)
    Function sum (children 1)
     ExpressionList (children 1)
      Identifier in_sample
   TablesInSelectQuery (children 1)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      Subquery (children 1)
       SelectWithUnionQuery (children 1)
        ExpressionList (children 1)
         SelectQuery (children 4)
          ExpressionList (children 1)
           WithElement (children 1)
            Subquery (children 1)
             SelectWithUnionQuery (children 1)
              ExpressionList (children 1)
               SelectQuery (children 3)
                ExpressionList (children 2)
                 Identifier user_id
                 Function modulo (alias in_sample) (children 1)
                  ExpressionList (children 2)
                   Function rand (children 1)
                    ExpressionList
                   Literal UInt64_2
                TablesInSelectQuery (children 1)
                 TablesInSelectQueryElement (children 1)
                  TableExpression (children 1)
                   TableIdentifier users_items
                ExpressionList (children 1)
                 Identifier user_id
          ExpressionList (children 2)
           Identifier user_id
           Identifier in_sample
          TablesInSelectQuery (children 1)
           TablesInSelectQueryElement (children 1)
            TableExpression (children 1)
             TableIdentifier RandomUsers
          Function equals (children 1)
           ExpressionList (children 2)
            Identifier in_sample
            Literal UInt64_0
