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kurs:correlated_subquery [2014/09/10 21:22] 127.0.0.1 external edit |
kurs:correlated_subquery [2022/03/15 10:39] (current) admin |
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+ | <code> | ||
+ | with cte_multiple_last_names as ( | ||
+ | select last_name, | ||
+ | count(*) c | ||
+ | from hr.employees | ||
+ | group by last_name | ||
+ | having count(*) > 1 | ||
+ | order by c desc | ||
+ | ) | ||
+ | select employee_id, | ||
+ | first_name, | ||
+ | last_name | ||
+ | from hr.employees where last_name | ||
+ | in (select last_name from cte_multiple_last_names) | ||
+ | |||
+ | |||
+ | select | ||
+ | emp.first_name, | ||
+ | emp.last_name | ||
+ | from | ||
+ | hr.employees emp | ||
+ | where | ||
+ | (select count(last_name) from hr.employees emp_sub where emp_sub.last_name = emp.last_name) > 1 | ||
+ | |||
<code> | <code> | ||
select first_name, last_name, e.employee_id, c from employees e, | select first_name, last_name, e.employee_id, c from employees e, | ||
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and outer.fhz_name = inner.fhz_name | and outer.fhz_name = inner.fhz_name | ||
)) > 1 | )) > 1 | ||
+ | </code> | ||
+ | |||
+ | <code> | ||
+ | with emp_per_country as ( | ||
+ | SELECT dep.department_id, | ||
+ | department_name, | ||
+ | cou.country_id, | ||
+ | country_name, | ||
+ | COUNT(employee_id) c | ||
+ | FROM hr.employees emp | ||
+ | JOIN hr.departments dep | ||
+ | ON emp.department_id = dep.department_id | ||
+ | JOIN hr.locations loc | ||
+ | ON loc.location_id = dep.location_id | ||
+ | JOIN hr.countries cou | ||
+ | ON cou.country_id = loc.country_id | ||
+ | GROUP BY dep.department_id, department_name, cou.country_id, country_name | ||
+ | ORDER BY COUNT(employee_id) DESC | ||
+ | ) | ||
+ | select country_name, department_name, c from emp_per_country o | ||
+ | where c = (select max(c) from emp_per_country where country_id = o.country_id) | ||
</code> | </code> |