advanced sql

Author: letsdeepchat

ADVANCED SELECT AND JOINS/1789. Primary Department for Each Employee.sql

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+# Write your MySQL query statement below
+SELECT employee_id, department_id
+FROM  Employee
+WHERE primary_flag = 'Y'
+    OR
+    employee_id IN (
+        SELECT employee_id
+        FROM Employee
+        GROUP BY employee_id
+        HAVING COUNT(employee_id) = 1
+    );