mysql> use qq;
Database changed
mysql> #查询本店价比市场价省的钱，并且要求省钱200元以上的取出来
mysql> select goods_id,market_price,shop_price,(market_price-shop_price) as discount from goods where having discount>200;
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'having discount>200' at line 1
mysql> select goods_id,market_price,shop_price,(market_price-shop_price) as discount from goods having discount>200;
+----------+--------------+------------+----------+
| goods_id | market_price | shop_price | discount |
+----------+--------------+------------+----------+
| 1 | 1665.60 | 1388.00 | 277.60 |
| 9 | 2757.60 | 2298.00 | 459.60 |
| 10 | 1593.60 | 1328.00 | 265.60 |
| 13 | 1573.20 | 1311.00 | 262.20 |
| 14 | 3150.00 | 2625.00 | 525.00 |
| 17 | 2760.00 | 2300.00 | 460.00 |
| 18 | 3453.60 | 2878.00 | 575.60 |
| 21 | 2400.00 | 2000.00 | 400.00 |
| 22 | 7198.80 | 5999.00 | 1199.80 |
| 23 | 4440.00 | 3700.00 | 740.00 |
| 24 | 2400.00 | 2000.00 | 400.00 |
| 31 | 1604.39 | 1337.00 | 267.39 |
| 32 | 3612.00 | 3010.00 | 602.00 |
+----------+--------------+------------+----------+
13 rows in set (0.01 sec)
mysql> #where和having不能同时出现
mysql> #查询出每种商品所积压的货款
mysql> select goods_id,shop_price,goods_number,shop_price*goods_number as jy from goods;
+----------+------------+--------------+-----------+
| goods_id | shop_price | goods_number | jy |
+----------+------------+--------------+-----------+
| 1 | 1388.00 | 1 | 1388.00 |
| 4 | 58.00 | 17 | 986.00 |
| 3 | 68.00 | 24 | 1632.00 |
| 5 | 20.00 | 8 | 160.00 |
| 6 | 42.00 | 15 | 630.00 |
| 7 | 100.00 | 20 | 2000.00 |
| 8 | 399.00 | 1 | 399.00 |
| 9 | 2298.00 | 4 | 9192.00 |
| 10 | 1328.00 | 7 | 9296.00 |
| 11 | 1300.00 | 1 | 1300.00 |
| 12 | 983.00 | 8 | 7864.00 |
| 13 | 1311.00 | 8 | 10488.00 |
| 14 | 2625.00 | 1 | 2625.00 |
| 15 | 788.00 | 3 | 2364.00 |
| 16 | 823.33 | 0 | 0.00 |
| 17 | 2300.00 | 1 | 2300.00 |
| 18 | 2878.00 | 1 | 2878.00 |
| 19 | 858.00 | 12 | 10296.00 |
| 20 | 280.00 | 12 | 3360.00 |
| 21 | 2000.00 | 40 | 80000.00 |
| 22 | 5999.00 | 1 | 5999.00 |
| 23 | 3700.00 | 8 | 29600.00 |
| 24 | 2000.00 | 100 | 200000.00 |
| 25 | 48.00 | 2 | 96.00 |
| 26 | 19.00 | 2 | 38.00 |
| 27 | 95.00 | 2 | 190.00 |
| 28 | 45.00 | 0 | 0.00 |
| 29 | 90.00 | 0 | 0.00 |
| 30 | 18.00 | 9 | 162.00 |
| 31 | 1337.00 | 1 | 1337.00 |
| 32 | 3010.00 | 4 | 12040.00 |
+----------+------------+--------------+-----------+
31 rows in set (0.00 sec)
mysql> #查询该店积压的总货款，每个商品的积压货款之和
mysql> select sum(goods_number*shop_price) from goods;
+------------------------------+
| sum(goods_number*shop_price) |
+------------------------------+
| 398620.00 |
+------------------------------+
1 row in set (0.00 sec)
mysql> #查询每个栏目下的积压货款
mysql> select cat_id,sum(shop_price*goods_number) from goods group by cat_id;
+--------+------------------------------+
| cat_id | sum(shop_price*goods_number) |
+--------+------------------------------+
| 2 | 0.00 |
| 3 | 356235.00 |
| 4 | 6891.00 |
| 5 | 29600.00 |
| 8 | 4618.00 |
| 11 | 790.00 |
| 13 | 134.00 |
| 14 | 162.00 |
| 15 | 190.00 |
+--------+------------------------------+
9 rows in set (0.00 sec)
mysql> #查询出栏目积压货款，，并筛选出积压货款>20000的栏目
mysql> select cat_id,sum(goods_number*shop_price) as jhk
-> from goods group by cat_id
-> having jhk>20000;
+--------+-----------+
| cat_id | jhk |
+--------+-----------+
| 3 | 356235.00 |
| 5 | 29600.00 |
+--------+-----------+
2 rows in set (0.00 sec)
mysql> create table result(
-> name varchar(20) default null,
-> subject varchar(20) default null,
-> score tinyint(4) default null
-> )engine myisam charset utf8;
Query OK, 0 rows affected (0.08 sec)
mysql> insert into result{
-> \c
mysql> insert into result
-> values
-> ('张三','数学',90),
-> ('张三','语文',50),
-> ('张三','地理',40)
-> ;
ERROR 1366 (HY000): Incorrect string value: '\xD5\xC5\xC8\xFD' for column 'name' at row 1
mysql> set names gnk;
ERROR 1115 (42000): Unknown character set: 'gnk'
mysql> set names gbk;
Query OK, 0 rows affected (0.00 sec)
mysql> insert into result
-> values
-> ('张三','数学',90),
-> ('张三','语文',50),
-> ('张三','地理',40);
Query OK, 3 rows affected (0.02 sec)
Records: 3 Duplicates: 0 Warnings: 0
mysql> insert into result
-> values
-> ('','',55),
-> ('张三','数学',90),\c
mysql> insert into result
-> values
-> ('李四','语文',55),
-> ('李四','政治',45),
-> ('王五','政治',30);
Query OK, 3 rows affected (0.00 sec)
Records: 3 Duplicates: 0 Warnings: 0
mysql> select * from result;
+------+---------+-------+
| name | subject | score |
+------+---------+-------+
| 张三 | 数学 | 90 |
| 张三 | 语文 | 50 |
| 张三 | 地理 | 40 |
| 李四 | 语文 | 55 |
| 李四 | 政治 | 45 |
| 王五 | 政治 | 30 |
+------+---------+-------+
6 rows in set (0.03 sec)
mysql> #查询2门及2门以上不及格者的平均成绩
mysql> select name,avg(subject) form result group by name having subject<60;
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'result group by name having subject<60' at line 1
mysql> select name,avg(subject) form result group by name having score<60;
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'result group by name having score<60' at line 1
mysql> select name,avg(score) form result group by name where score<60;
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'result group by name where score<60' at line 1
mysql> select name,score,score<60 from result group by name;
+------+-------+----------+
| name | score | score<60 |
+------+-------+----------+
| 张三 | 90 | 0 |
| 李四 | 55 | 1 |
| 王五 | 30 | 1 |
+------+-------+----------+
3 rows in set (0.02 sec)
mysql> select name,score,score<60 from result;
+------+-------+----------+
| name | score | score<60 |
+------+-------+----------+
| 张三 | 90 | 0 |
| 张三 | 50 | 1 |
| 张三 | 40 | 1 |
| 李四 | 55 | 1 |
| 李四 | 45 | 1 |
| 王五 | 30 | 1 |
+------+-------+----------+
6 rows in set (0.00 sec)
mysql> select name,score,sum(score<60) from result group by name;
+------+-------+---------------+
| name | score | sum(score<60) |
+------+-------+---------------+
| 张三 | 90 | 2 |
| 李四 | 55 | 2 |
| 王五 | 30 | 1 |
+------+-------+---------------+
3 rows in set (0.00 sec)
mysql> select name,score,sum(score<60) as g from result group by name having g>=2;
+------+-------+------+
| name | score | g |
+------+-------+------+
| 张三 | 90 | 2 |
| 李四 | 55 | 2 |
+------+-------+------+
2 rows in set (0.00 sec)
mysql> select name,avg(score) from result group by name having sum(score<60)>=2;
+------+------------+
| name | avg(score) |
+------+------------+
| 张三 | 60.0000 |
| 李四 | 50.0000 |
+------+------------+
2 rows in set (0.00 sec)
mysql> select name,avg(score) from result group by name where sum(score<60)>=2;
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'where sum(score<60)>=2' at line 1
mysql> select name,avg(score) from result group by name having sum(score<60)>=2;
+------+------------+
| name | avg(score) |
+------+------------+
| 张三 | 60.0000 |
| 李四 | 50.0000 |
+------+------------+
2 rows in set (0.00 sec)
mysql> select name,avg(score),sum(score<60) as g from result group by name having g>=2;
+------+------------+------+
| name | avg(score) | g |
+------+------------+------+
| 张三 | 60.0000 | 2 |
| 李四 | 50.0000 | 2 |
+------+------------+------+
2 rows in set (0.00 sec)
mysql> #首先将平均数求出，然后再筛选出挂科两科及两科以上的同学，筛选用score<60，是否及格用0,1表示，然后求和就是挂科数，筛选出>=2的，整出结果
mysql> #找出每个栏目下id号最大的商品
mysql> select goods_id,cat_id,goods_name from goods group by cat_id order by goods_id desc limit 1;
+----------+--------+-----------------+
| goods_id | cat_id | goods_name |
+----------+--------+-----------------+
| 29 | 14 | 移动100元充值卡 |
+----------+--------+-----------------+
1 row in set (0.03 sec)
mysql> select goods_id,cat_id,goods_name from goods group by cat_id having goods_id order by goods_id desc limit 1;
+----------+--------+-----------------+
| goods_id | cat_id | goods_name |
+----------+--------+-----------------+
| 29 | 14 | 移动100元充值卡 |
+----------+--------+-----------------+
1 row in set (0.00 sec)
mysql> select goods_id,cat_id,goods_name from goods group by cat_id having goods_id order by goods_id desc;
+----------+--------+-----------------------+
| goods_id | cat_id | goods_name |
+----------+--------+-----------------------+
| 29 | 14 | 移动100元充值卡 |
| 27 | 15 | 联通100元充值卡 |
| 25 | 13 | 小灵通/固话50元充值卡 |
| 23 | 5 | 诺基亚N96 |
| 16 | 2 | 恒基伟业G101 |
| 8 | 3 | 飞利浦9@9v |
| 5 | 11 | 索爱原装M2卡读卡器 |
| 4 | 8 | 诺基亚N85原装充电器 |
| 1 | 4 | KD876 |
+----------+--------+-----------------------+
9 rows in set (0.00 sec)
mysql> select goods_id,cat_id,goods_name from goods group by cat_id having max(goods_id);
+----------+--------+-----------------------+
| goods_id | cat_id | goods_name |
+----------+--------+-----------------------+
| 16 | 2 | 恒基伟业G101 |
| 8 | 3 | 飞利浦9@9v |
| 1 | 4 | KD876 |
| 23 | 5 | 诺基亚N96 |
| 4 | 8 | 诺基亚N85原装充电器 |
| 5 | 11 | 索爱原装M2卡读卡器 |
| 25 | 13 | 小灵通/固话50元充值卡 |
| 29 | 14 | 移动100元充值卡 |
| 27 | 15 | 联通100元充值卡 |
+----------+--------+-----------------------+
9 rows in set (0.00 sec)
mysql> select goods_id,cat_id,goods_name from goods group by cat_id where cat_id having max(goods_id);
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'where cat_id having max(goods_id)' at line 1
mysql> select goods_name,goods_id,cat_id from (select goods_name,cat_id,goods_id from goods order by goods_id desc)as temp group by cat_id;
+------------------------------+----------+--------+
| goods_name | goods_id | cat_id |
+------------------------------+----------+--------+
| 恒基伟业G101 | 16 | 2 |
| 诺基亚N85 | 32 | 3 |
| 夏新T5 | 18 | 4 |
| 诺基亚N96 | 23 | 5 |
| 诺基亚N85原装立体声耳机HS-82 | 7 | 8 |
| 胜创KINGMAX内存卡 | 6 | 11 |
| 小灵通/固话20元充值卡 | 26 | 13 |
| 移动20元充值卡 | 30 | 14 |
| 联通50元充值卡 | 28 | 15 |
+------------------------------+----------+--------+
9 rows in set (0.03 sec)
mysql> #必须要用到子查询
