SELECT mcategory apackage_name COUNTDISTINCT CASE WHEN aaction_type = itemShow THEN auserid END AS exposure_count COUNTDISTINCT CASE WHEN aaction_type = itemClick THEN auserid END AS cli

This SQL query selects the category and package name from the mapping_table and counts the number of distinct users who either showed, clicked or both on an item in the app. The Click-Through-Rate (CTR) is also calculated by dividing the number of distinct users who clicked an item by the number of distinct users who showed an item. The results are grouped by category and package name and only those with an exposure count greater than 100 are displayed. The results are then sorted first by category and then by CTR in descending order.