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

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

|1607|[Sellers With No Sales](https://leetcode.com/problems/sellers-with-no-sales/)|[Solution](../master/database/_1607.sql)|| Easy|

|1581|[Customer Who Visited but Did Not Make Any Transactions](https://leetcode.com/problems/customer-who-visited-but-did-not-make-any-transactions/)|[Solution](../master/database/_1581.sql)|| Easy|

|1543|[Fix Product Name Format](https://leetcode.com/problems/fix-product-name-format/)|[Solution](../master/database/_1543.sql)|| Easy|

|1517|[Find Users With Valid E-Mails](https://leetcode.com/problems/find-users-with-valid-e-mails/)|[Solution](../master/database/_1517.sql)|| Easy|

|1495|[Friendly Movies Streamed Last Month](https://leetcode.com/problems/friendly-movies-streamed-last-month/)|[Solution](../master/database/_1495.sql)|| Easy|

select customer_idas customer_id,count(*)as count_no_transfrom Visitswhere visit_id notin (select distinct visit_idfrom Transactions)group by customer_id;