Hello @Basu212, Take a look at the below thread:
https://experienceleaguecommunities.adobe.com/t5/adobe-analytics-blogs/sample-sql-queries-to-query-a...
7. To calculate time spent
SELECT CONCAT(post_visid_high, post_visid_low, visit_num, visit_start_time_gmt) as visit_id,
visit_page_num,
post_cust_hit_time,
CASE
WHEN LEAD(visit_id) OVER (ORDER BY CONCAT(post_visid_high, post_visid_low, visit_num, visit_start_time_gmt), visit_page_num) = visit_id AND LEAD(visit_page_num) OVER (ORDER BY CONCAT(post_visid_high, post_visid_low, visit_num, visit_start_time_gmt), visit_page_num) > visit_page_num
THEN LEAD(post_cust_hit_time) OVER (ORDER BY CONCAT(post_visid_high, post_visid_low, visit_num, visit_start_time_gmt), visit_page_num) - post_cust_hit_time
ELSE NULL
END as time_spent
FROM your_data_feed_name
WHERE date >= 'your_start_date'
AND date <= 'your_end_date'
Hope this helps!