When two tables in a report have a one-to-many relationship, the program retrieves the data in different ways depending on:
Record selection criteria.
Whether you are creating a single report based on linked tables or a primary report that contains a subreport.
As a general rule, if you have indexed tables, linked indexed fields, or range limiting record selection criteria based on the indexed fields, the program needs to read the same number of records whether you are linking tables in a single report or using subreports. Since each subreport is run as a separate report, linked tables may have a performance advantage.