Disable drill down at particular level

You want to allow drill up on that level you need to do following

goto

1) Data - Drill Behaviour - select that particular level, both in drill up and drill down section.
Goto Advanced tab and for that particular level ; Define drill up behaviour as "Depth based Expression" and
Drill down behaviour as "Preserve".
This will enable drill up and disable drill down for that particular level.
2) Data - Drill Behaviour - Select that particular level and set the depth based expression to for example 2, that column or hierarchy will drill only till level 2.

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