Generally you want to use parameter fields when you want to dynamically define the way the data is organized or what data is selected each time you run the report. Otherwise using the select expert is fine. An example: You always want the last 30 days of sales from the day the report is run. Use the select expert without any parameters. You want a to choose a 30 day range of sales, use parameters that are passed into the select expert. Parameter use really depends on that you want to accomplish with the report.

 

Be aware that part of the question here is also how you are deploying the reports (say with crystal viewer). Parameters do not allways display the same way depending on this so they could be useful or confusing. Test it at the deployment side as well as when you are building the report.

A few examples of using parameters:

1) Parameter of a date range for the data allows your user running the report to defing their own range.

2) Parameter of a "Vendor" can let the end user select a specific vendor(s) they want to view instead of all of the vendors in the DB.

3) conditional grouping - you can set a report to allow the user to invert how the data is grouped. For example parameter option 1 may group by Vendor then Sales person where as Option 2 may group by Sales person then Vendor.

 

Basically you are setting up a report that the end user has much more control over what is returned when you use parameter fields.

 

You can often do similar things by using the select expert without passing Parameters but this means you are pre-defing what and how the report will show and not giving the end user the option.

Examples of just using a select statement without a parameter field: