Antal personer i en aldersgruppe

CREATE TABLE person (firstname VARCHAR(32), lastname VARCHAR(32), birthday DATETIME, PRIMARY KEY(firstname,lastname));

INSERT INTO person VALUES('Anders', 'Andersen', 19810702);
INSERT INTO person VALUES('Børge', 'Børgesen', 19810629);
INSERT INTO person VALUES('Christian', 'Christiansen', 19790702);

SELECT * FROM person;

SELECT YEAR(NOW())-YEAR(birthday)-IF(DAYOFYEAR(NOW())<DAYOFYEAR(birthday),1,0) AS age FROM person;

SELECT 5*FLOOR(age/5),5*FLOOR(age/5)+4,COUNT(*)
FROM (SELECT YEAR(NOW())-YEAR(birthday)-IF(DAYOFYEAR(NOW())<DAYOFYEAR(birthday),1,0) AS age FROM person) x
GROUP BY 5*FLOOR(age/5);

DROP TABLE person;

mysql> CREATE TABLE person (firstname VARCHAR(32), lastname VARCHAR(32), birthday DATETIME, PRIMARY KEY(firstname,lastname));
Query OK, 0 rows affected (0.01 sec)

mysql>
mysql> INSERT INTO person VALUES('Anders', 'Andersen', 19810702);
Query OK, 1 row affected (0.00 sec)

mysql> INSERT INTO person VALUES('Borge', 'Borgesen', 19810629);
Query OK, 1 row affected (0.00 sec)

mysql> INSERT INTO person VALUES('Christian', 'Christiansen', 19790702);
Query OK, 1 row affected (0.00 sec)

mysql>
mysql> SELECT * FROM person;
+-----------+--------------+---------------------+
| firstname | lastname    | birthday            |
+-----------+--------------+---------------------+
| Anders    | Andersen    | 1981-07-02 00:00:00 |
| Borge    | Borgesen    | 1981-06-29 00:00:00 |
| Christian | Christiansen | 1979-07-02 00:00:00 |
+-----------+--------------+---------------------+
3 rows in set (0.00 sec)

mysql>
mysql> SELECT YEAR(NOW())-YEAR(birthday)-IF(DAYOFYEAR(NOW())<DAYOFYEAR(birthday),1,0) AS age FROM person;
+------+
| age  |
+------+
|  24 |
|  25 |
|  26 |
+------+
3 rows in set (0.00 sec)

mysql>
mysql> SELECT 5*FLOOR(age/5),5*FLOOR(age/5)+4,COUNT(*)
    -> FROM (SELECT YEAR(NOW())-YEAR(birthday)-IF(DAYOFYEAR(NOW())<DAYOFYEAR(birthday),1,0) AS age FROM person) x
    -> GROUP BY 5*FLOOR(age/5);
+----------------+------------------+----------+
| 5*FLOOR(age/5) | 5*FLOOR(age/5)+4 | COUNT(*) |
+----------------+------------------+----------+
|            20 |              24 |        1 |
|            25 |              29 |        2 |
+----------------+------------------+----------+
2 rows in set (0.00 sec)

mysql>
mysql> DROP TABLE person;
Query OK, 0 rows affected (0.00 sec)

det må ihvertfald kunne give nogle ideer

så er der lidt at arbejde med ;)
tak skal du have

saa ligger jeg et svar

Tusind tak for hjælpen, det var meget brugbart :)