ORACLE SQL: Show the department name, id, and # of employees of the dept. that has the least # of employees -
note, homework question!
show department number, department name, , number of employees working in department has least number of employees.
i can figure out how many employees each department has, how show department least number of employees?
select employees.department_id, departments.department_name, count(employee_id) employees join departments on employees.department_id = departments.department_id group employees.department_id, departments.department_name;
what need having
clause, allows apply condition after group by
clause applied. in other words, allows apply condition on aggregate expression:
select employees.department_id, departments.department_name, count(employee_id) employees join departments on employees.department_id = departments.department_id group employees.department_id, departments.department_name; having count(*) > 5 -- here!
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