3 Months back, I was in your shoes...evaluating QV. Anyway here is the information...
A multiple selection within a list box is usually interpreted as logical "OR", meaning that data entries associated with any of the selected values will be shown. However, under certain circumstances it can be set to be interpreted as "AND", implying that QlikView must find the solutions that are associated to all the selected field values, not just to any of them.
The mode for the field is set in the list box dialog (Object menu >> Properties >> General >> And mode).
A value in a list box in "And" mode will be marked with an ampersand "&" when selected.
A field cannot always be set to logical and mode. The reason for this is that the and alternative is logically meaningful only if the concerned field is
linked to only one other field. The following criteria must be fulfilled:
• the field must only exist in one logical table,
• the field must be the second column, and
• the field must be distinct.
Also you should explore "Set Analysis" features. With Set Analysis the possibilities are endless... I mean you can do pretty much everything . I am also attaching a simple presentation on Set Analysis for your consumption.
Do let me know if you need further help.
Cheers - DV