Maintaining cardinality of rows while joining worksheets from a database including receiving a request to join, to a first worksheet, a second worksheet from the database; for each row in the first worksheet: generating a join row for data from the second worksheet on the database; in response to determining that there is at least one matching row in the second worksheet on the database: compare a maximum value and a minimum value for each column in each row of the at least one matching row; if the maximum value and the minimum value match, store a matching value in a corresponding column of the join row; and if the maximum value and the minimum value do not match, store a multiple value indication in the corresponding column of the join row; and presenting the join row adjacent to a corresponding row in the first worksheet.