Crystal Report: How can I use a list of parameter

问题:

Background

I have a Crystal Report.

For multiple items entered into a parameter (which I believe becomes a string array), I would like it to group by those values and then run a number of sub-reports for each group item.

Goal

For items entered as part of a parameter (which allows multiple items), use those items as a group so that I can see multiple sub-reports for those items (including if no data can be found for a given item).

To clarify, the desired process is:

• User runs the report
• User is prompted to enter one or more item numbers into the ItemNumbers parameter
• The ItemNumbers parameter is used to create groupings
• The groupings run several sub-reports for each group (presumably in the group footer)
• The users see the results (or non-results) for each of the subreports under each item group.

Roadblocks / attempts so far

• Tried to use the parameter as the grouping. This isn't possible as it does not show up in the list of things I can select for a grouping.
• Tried to use a formula to hold the value of the parameter. This is not possible because formulas cannot result in an array.
• Tried to create a StringArray variable to hold the parameter entries, but since it also must be referenced in a selection formula and formulas can't be arrays, this failed.

回答1:

You can't group on a parameter field. You will need to use it to filter your recordset, then group on one of its (recordset's) fields.

** edit **

I would create a number of queries that compare the individual transaction tables to the 'main' table (LEFT OUTER JOIN), then UNION these queries. Create a report, using this query as the source of a Command object.