add 1978

Author: fishercoder1534

Diff for: database/_1978.sql

@@ -0,0 +1,7 @@
+-- Write your PostgreSQL query statement below
+select employee_id
+from Employees
+where manager_id not in
+      (select employee_id from Employees)
+  and salary < 30000
+order by 1 asc

Diff for: paginated_contents/database/README.md

@@ -7,6 +7,7 @@
 | 2082 |[The Number of Rich Customers](https://leetcode.com/problems/the-number-of-rich-customers/)| [Solution](https://github.com/fishercoder1534/Leetcode/blob/master/database/_2082.sql)                                || Easy |
 | 2072 |[The Winner University](https://leetcode.com/problems/the-winner-university/)| [Solution](https://github.com/fishercoder1534/Leetcode/blob/master/database/_2072.sql)                                || Easy |
 | 2026 |[Low-Quality Problems](https://leetcode.com/problems/low-quality-problems/)| [Solution](https://github.com/fishercoder1534/Leetcode/blob/master/database/_2026.sql)                                || Easy |
+| 1978 |[Employees Whose Manager Left the Company](https://leetcode.com/problems/employees-whose-manager-left-the-company/)| [Solution](https://github.com/fishercoder1534/Leetcode/blob/master/database/_1978.sql)                                || Easy |
 | 1789 |[Primary Department for Each Employee](https://leetcode.com/problems/primary-department-for-each-employee/)| [Solution](https://github.com/fishercoder1534/Leetcode/blob/master/database/_1789.sql)                                || Easy |
 | 1757 |[Recyclable and Low Fat Products](https://leetcode.com/problems/recyclable-and-low-fat-products/)| [Solution](https://github.com/fishercoder1534/Leetcode/blob/master/database/_1757.sql)                                || Easy |
 | 1741 |[Find Total Time Spent by Each Employee](https://leetcode.com/problems/find-total-time-spent-by-each-employee/)| [Solution](https://github.com/fishercoder1534/Leetcode/blob/master/database/_1741.sql)                                || Easy |