| # | Title | Solutions | Video | Difficulty | Tag

|-----|----------------|---------------|---------------|---------------|-------------

|1709|[Biggest Window Between Visits](https://leetcode.com/problems/biggest-window-between-visits/)|[Solution](../master/database/_1709.sql)|| Medium|

|1693|[Daily Leads and Partners](https://leetcode.com/problems/daily-leads-and-partners/)|[Solution](../master/database/_1693.sql)|| Easy|

|1683|[Invalid Tweets](https://leetcode.com/problems/invalid-tweets/)|[Solution](../master/database/_1683.sql)|| Easy|

|1677|[Product's Worth Over Invoices](https://leetcode.com/problems/products-worth-over-invoices/)|[Solution](../master/database/_1677.sql)|| Easy|

with diff_tableas (

select user_id, datediff(lead(visit_date,1,'2021-1-1') over (partition by user_idorder by visit_date), visit_date)as difffrom UserVisits

)

select user_id,max(diff)as biggest_windowfrom diff_tablegroup by user_idorder by user_id