mysql分组函数

1. id name dept_id salary manager_id
2. 0001 wangda 101 8500[NULL]
3. 0002 wanger 1033 000 0009
4. 0003 wangsan 102 4000 0006
5. 0004 wangsi 104 2000 0005
6. 0005 wangwu 104 6000 0001
7. 0006 wangliu 102 7000 0001
8. 0007 wangqi 105 5000 0008
9. 0008 wangba 105 5500 0001
10. 0009 wangjiu 103 6000 0001
11. 0010 wangshi 104 900 0005
12. 0011 wangsy 103 5000 0009
13. 0012 wangse [NULL]3000[NULL]

1. SELECT
2. dept_id,
3. avg(salary)
4. FROM
5. person
6. GROUP BY
7. dept_id;

1. dept_id avg(salary)
2. [NULL] 3000.000000
3. 101 8500.000000
4. 102 5500.000000
5. 103 4666.666667
6. 104 2966.666667
7. 105 5250.000000

1. SELECT
2. p.dept_id,
3. dept_name,
4. avg(salary)
5. FROM
6. person p,dept d
7. where p.dept_id = d.dept_id
8. GROUP BY
9. p.dept_id
10. HAVING
11. avg(salary)>5000;

1. dept_id dept_name avg(salary)
2. 101 zongwu 8500.000000
3. 102 zhenggong 5500.000000
4. 105 renshi 5250.000000

mysql分组函数

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