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--- kurs:group_by_beispiele [2012/09/25 17:22]
127.0.0.1 external edit
+++ kurs:group_by_beispiele [2020/05/18 11:25] (current)
admin
@@ Line 1: / Line 1: @@
+<code>
+select
+    department_name,
+    count(*) c
+from employees e join departments d
+on e.department_id = d.department_id
+group by
+    department_name
+having count(*) >= 5
+order by c desc
+</code>
+<code>
+with ym as (
+select employee_id,
+    --   extract(year from hire_date) y,
+       extract(month from hire_date) m
+       from employees
+)
+select m, count(employee_id)
+  from ym
+       group by m
+       order by m
+</code>
+<code>
+with gehaltklassen as (
+select salary, case when salary < 7000 then 0
+            when salary < 12000 then 1
+            else 2 end gehaltklasse
+from employees
+)
+select gehaltklasse, dg, count(dg) from (
+   select gehaltklasse, decode(gehaltklasse,
+, 'wenig',
+, 'mittel',
+, 'viel') dg
+     from gehaltklassen )
+group by gehaltklasse, dg
+order by gehaltklasse
+</code>
 <code>

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