Printing labels from a list of values separated by comma

Hello,

I have to print labels from a list of part number values formated like that : '123344','456789','963254'

in only one parameter {?PART_NO}

So, I'm trying to use a select record in Crystal Report.

when I put a simple condition, I have the result quickly

{INVENT.PART_NO} = {?PART_NO}

=> when I look at the SQL query in Crystal I have this select condition right mentionned.

when I want to use the IN condition it reduces the speed of the query

{INVENT_PART.PART_NO} in {?PART_NO}

=> when I look at the SQL query in Crystal I haven't this select condition mentionned => it means that Crystal reads all the records (40000 records) to select the data after (?)

How do I improve that ?

I've read some posts dealing with calling a sub report

Is it possible to call x times a sub report with, for each call, a parameter ?

This parameter should be a part number, belonging to the string like '123344','456789','963254','999999' ?