51、使用通配符构造查询条件(1)
有数据表:Products,表中数据如下:
| prod_name | prod_desc |
|---|---|
| a0011 | usb |
| a0019 | iphone13 |
| b0019 | gucci t-shirts |
| c0019 | gucci toy |
| d0019 | lego toy |
【问题】编写 SQL 语句,从 Products 表中检索产品名称(prod_name)和描述(prod_desc),仅返回描述中包含 toy 一词的产品名称。查询结果如下:
| prod_name | prod_desc |
|---|---|
| c0019 | gucci toy |
| d0019 | lego toy |
表结构及数据如下:
/*
DROP TABLE IF EXISTS `Products`;
CREATE TABLE IF NOT EXISTS `Products` (
`prod_name` VARCHAR(255) NOT NULL COMMENT '产品 ID',
`prod_desc` VARCHAR(255) NOT NULL COMMENT '产品名称'
);
INSERT INTO `Products` VALUES ('a0011','usb'),
('a0019','iphone13'),
('b0019','gucci t-shirts'),
('c0019','gucci toy'),
('d0019','lego toy');
*/
解答:
mysql> select prod_name, prod_desc from Products where prod_desc like '%toy%';
+-----------+-----------+
| prod_name | prod_desc |
+-----------+-----------+
| c0019 | gucci toy |
| d0019 | lego toy |
+-----------+-----------+
2 rows in set (0.02 sec)
52、使用通配符构造查询条件(2)
有数据表:Products,表中数据如下:
| prod_name | prod_desc |
|---|---|
| a0011 | usb |
| a0019 | iphone13 |
| b0019 | gucci t-shirts |
| c0019 | gucci toy |
| d0019 | lego toy |
【问题】编写 SQL 语句,从 Products 表中检索产品名称(prod_name)和描述(prod_desc),仅返回描述中未出现 toy 一词的产品,并且按 ”产品名称“ 对结果进行排序。查询结果如下:
| prod_name | prod_desc |
|---|---|
| a0011 | usb |
| a0019 | iphone13 |
| b0019 | gucci t-shirts |
解答:
/*
select prod_name, prod_desc from Products
where prod_desc not like '%toy%' order by prod_name;
*/
mysql> select prod_name, prod_desc from Products
-> where prod_desc not like '%toy%' order by prod_name;
+-----------+----------------+
| prod_name | prod_desc |
+-----------+----------------+
| a0011 | usb |
| a0019 | iphone13 |
| b0019 | gucci t-shirts |
+-----------+----------------+
3 rows in set (0.00 sec)
53、使用通配符构造查询条件(3)
有数据表:Products,表中数据如下:
| prod_name | prod_desc |
|---|---|
| a0011 | usb |
| a0019 | iphone13 |
| b0019 | gucci t-shirts |
| c0019 | gucci toy |
| d0019 | lego carrots toy |
【问题】编写 SQL 语句,从 Products 表中检索产品名称(prod_name)和描述(prod_desc),仅返回描述中同时出现 toy 和 carrots 的产品。查询结果如下:
| prod_name | prod_desc |
|---|---|
| d0019 | lego carrots toy |
表结构及数据如下:
/*
DROP TABLE IF EXISTS `Products`;
CREATE TABLE IF NOT EXISTS `Products` (
`prod_name` VARCHAR(255) NOT NULL COMMENT '产品 ID',
`prod_desc` VARCHAR(255) NOT NULL COMMENT '产品名称'
);
INSERT INTO `Products` VALUES ('a0011','usb'),
('a0019','iphone13'),
('b0019','gucci t-shirts'),
('c0019','gucci toy'),
('d0019','lego carrots toy');
*/
解答:
/*
select prod_name, prod_desc from Products
where prod_desc like '%toy%' and prod_desc like '%carrots%';
*/
mysql> select prod_name, prod_desc from Products
-> where prod_desc like '%toy%' and prod_desc like '%carrots%';
+-----------+------------------+
| prod_name | prod_desc |
+-----------+------------------+
| d0019 | lego carrots toy |
+-----------+------------------+
1 row in set (0.00 sec)
54、使用通配符构造查询条件(4)
有数据表:Products,表中数据如下:
| prod_name | prod_desc |
|---|---|
| a0011 | usb |
| a0019 | iphone13 |
| b0019 | gucci t-shirts |
| c0019 | gucci toy |
| d0019 | lego toy carrots |
【问题】编写 SQL 语句,从 Products 表中检索产品名称(prod_name)和描述(prod_desc),返回在描述中以先后顺序同时出现 toy 和 carrots 的产品。查询结果如下:
| prod_name | prod_desc |
|---|---|
| d0019 | lego toy carrots |
表结构及数据如下:
/*
DROP TABLE IF EXISTS `Products`;
CREATE TABLE IF NOT EXISTS `Products` (
`prod_name` VARCHAR(255) NOT NULL COMMENT '产品 ID',
`prod_desc` VARCHAR(255) NOT NULL COMMENT '产品名称'
);
INSERT INTO `Products` VALUES ('a0011','usb'),
('a0019','iphone13'),
('b0019','gucci t-shirts'),
('c0019','gucci toy'),
('d0019','lego toy carrots ');
*/
解答:
mysql> select prod_name, prod_desc from Products where prod_desc like '%toy%carrots%';
+-----------+-------------------+
| prod_name | prod_desc |
+-----------+-------------------+
| d0019 | lego toy carrots |
+-----------+-------------------+
1 row in set (0.00 sec)
55、为列指定别名
有数据表:Vendors(供应商信息),vend_id(供应商 id)、vend_name(供应商名称)、vend_address(供应商地址)、vend_city(供应商城市),表中数据如下:
| vend_id | vend_name | vend_address | vend_city |
|---|---|---|---|
| a001 | tencent cloud | address1 | shenzhen |
| a002 | huawei cloud | address2 | dongguan |
| a003 | aliyun cloud | address3 | hangzhou |
| a003 | netease cloud | address4 | guangzhou |
【问题】编写 SQL 语句,从 Vendors 表中检索 vend_id、vend_name、vend_address 和 vend_city,将 vend_name 重命名为 vname,将 vend_city 重命名为 vcity,将 vend_address 重命名为 vaddress,结果按供应商名称升序排序。查询结果如下:
| vend_id | vname | vaddress | vcity |
|---|---|---|---|
| a003 | aliyun cloud | address3 | hangzhou |
| a002 | huawei cloud | address2 | dongguan |
| a003 | netease cloud | address4 | guangzhou |
| a001 | tencent cloud | address1 | shenzhen |
表结构及数据如下:
/*
DROP TABLE IF EXISTS `Vendors`;
CREATE TABLE IF NOT EXISTS `Vendors` (
`vend_id` VARCHAR(255) NOT NULL COMMENT '供应商id',
`vend_name` VARCHAR(255) NOT NULL COMMENT '供应商名称',
`vend_address` VARCHAR(255) NOT NULL COMMENT '供应商地址',
`vend_city` VARCHAR(255) NOT NULL COMMENT '供应商城市'
);
INSERT INTO `Vendors` VALUES ('a001','tencent cloud','address1','shenzhen'),
('a002','huawei cloud','address2','dongguan'),
('a003','aliyun cloud','address3','alibaba');
*/
解答:
/*
select vend_id, vend_name vname, vend_address vaddress, vend_city vcity
from Vendors order by vname;
*/
mysql> select vend_id, vend_name vname, vend_address vaddress, vend_city vcity
-> from Vendors order by vname;
+---------+---------------+----------+----------+
| vend_id | vname | vaddress | vcity |
+---------+---------------+----------+----------+
| a003 | aliyun cloud | address3 | alibaba |
| a002 | huawei cloud | address2 | dongguan |
| a001 | tencent cloud | address1 | shenzhen |
+---------+---------------+----------+----------+
3 rows in set (0.00 sec)
56、查询计算列
有数据表:Products,表中数据如下:
| prod_id | prod_price |
|---|---|
| a0011 | 9.49 |
| a0019 | 600 |
| b0019 | 1000 |
【问题】编写 SQL语句,从 Products 表中返回 prod_id、prod_price 和 sale_price。sale_price 是一个计算列,内容为 prod_price 列的 90%。查询结果如下:
| prod_id | prod_price | sale_price |
|---|---|---|
| a0011 | 9.49 | 8.541 |
| a0019 | 600 | 540 |
| b0019 | 1000 | 900 |
【示例解析】sale_price的价格是prod_price的90%
/*
DROP TABLE IF EXISTS `c`;
CREATE TABLE IF NOT EXISTS `Products` (
`prod_id` VARCHAR(255) NOT NULL COMMENT '产品 ID',
`prod_price` DOUBLE NOT NULL COMMENT '产品价格'
);
INSERT INTO `Products` VALUES ('a0011',9.49),
('a0019',600),
('b0019',1000);
*/
解答:
mysql> select prod_id, prod_price, prod_price * 0.9 sale_price from Products;
+---------+------------+------------+
| prod_id | prod_price | sale_price |
+---------+------------+------------+
| a0011 | 9.49 | 8.541 |
| a0019 | 600 | 540 |
| b0019 | 1000 | 900 |
+---------+------------+------------+
3 rows in set (0.02 sec)
57、函数的使用(1)
数据表:Customers,表中数据如下:
| cust_id | cust_name | cust_contact | cust_city |
|---|---|---|---|
| a1 | Andy Li | Andy Li | Oak Park |
| a2 | Ben Liu | Ben Liu | Oak Park |
| a3 | Tony Dai | Tony Dai | Oak Park |
| a4 | Tom Chen | Tom Chen | Oak Park |
| a5 | An Li | An Li | Oak Park |
| a6 | Lee Chen | Lee Chen | Oak Park |
| a7 | Hex Liu | Hex Liu | Oak Park |
【问题】编写 SQL 语句,返回顾客 ID(cust_id)、顾客名称(cust_name)和登录名(user_login)。其中登录名全部为大写字母,并由顾客联系人的前两个字符(cust_contact)和其所在城市的前三个字符(cust_city)组成。查询结果如下:
| cust_id | cust_name | user_login |
|---|---|---|
| a1 | Andy Li | ANOAK |
| a2 | Ben Liu | BEOAK |
| a3 | Tony Dai | TOOAK |
| a4 | Tom Chen | TOOAK |
| a5 | An Li | ANOAK |
| a6 | Lee Chen | LEOAK |
| a7 | Hex Liu | HEOAK |
表结构及数据如下:
/*
DROP TABLE IF EXISTS `Customers`;
CREATE TABLE IF NOT EXISTS `Customers`(
cust_id VARCHAR(255) NOT NULL COMMENT '客户id',
cust_name VARCHAR(255) NOT NULL COMMENT '客户姓名',
cust_contact VARCHAR(255) NOT NULL COMMENT '客户联系人',
cust_city VARCHAR(255) NOT NULL COMMENT '客户城市'
);
INSERT `Customers` VALUES ('a1','Andy Li','Andy Li','Oak Park'),('a2','Ben Liu','Ben Liu','Oak Park'),('a3','Tony Dai','Tony Dai','Oak Park'),('a4','Tom Chen','Tom Chen','Oak Park'),('a5','An Li','An Li','Oak Park'),('a6','Lee Chen','Lee Chen','Oak Park'),('a7','Hex Liu','Hex Liu','Oak Park');
*/
解答:
/*
select cust_id, cust_name,
upper(concat(left(cust_name, 2),left(cust_city, 3))) user_login
from Customers;
*/
mysql> select cust_id, cust_name,
-> upper(concat(left(cust_name, 2),left(cust_city, 3))) user_login
-> from Customers;
+---------+-----------+------------+
| cust_id | cust_name | user_login |
+---------+-----------+------------+
| a1 | Andy Li | ANOAK |
| a2 | Ben Liu | BEOAK |
| a3 | Tony Dai | TOOAK |
| a4 | Tom Chen | TOOAK |
| a5 | An Li | ANOAK |
| a6 | Lee Chen | LEOAK |
| a7 | Hex Liu | HEOAK |
+---------+-----------+------------+
7 rows in set (0.03 sec)
58、函数的使用(2)
数据表:Orders(订单表),表中的数据如下:
| order_num | order_date |
|---|---|
| a0001 | 2020-01-01 00:00:00 |
| a0002 | 2020-01-02 00:00:00 |
| a0003 | 2020-01-01 12:00:00 |
| a0004 | 2020-02-01 00:00:00 |
| a0005 | 2020-03-01 00:00:00 |
【问题】编写 SQL 语句,返回 2020 年 1 月的所有订单的订单号(order_num)和订单日期(order_date),并按订单日期升序排序。查询结果如下:
| order_num | order_date |
|---|---|
| a0001 | 2020-01-01 00:00:00 |
| a0003 | 2020-01-01 12:00:00 |
| a0002 | 2020-01-02 00:00:00 |
表结构及数据如下:
/*
DROP TABLE IF EXISTS `Orders`;
CREATE TABLE IF NOT EXISTS `Orders`(
order_num VARCHAR(255) NOT NULL COMMENT '订单号',
order_date TIMESTAMP NOT NULL COMMENT '订单日期'
);
INSERT `Orders` VALUES ('a0001','2020-01-01 00:00:00'),
('a0002','2020-01-02 00:00:00'),
('a0003','2020-01-01 12:00:00'),
('a0004','2020-02-01 00:00:00'),
('a0005','2020-03-01 00:00:00');
*/
解答:
/*
select order_num, order_date from Orders
where year(order_date) = 2020 and month(order_date) = 1
order by order_date;
*/
mysql> select order_num, order_date from Orders
-> where year(order_date) = 2020 and month(order_date) = 1
-> order by order_date;
+-----------+---------------------+
| order_num | order_date |
+-----------+---------------------+
| a0001 | 2020-01-01 00:00:00 |
| a0003 | 2020-01-01 12:00:00 |
| a0002 | 2020-01-02 00:00:00 |
+-----------+---------------------+
3 rows in set (0.00 sec)
59、聚合函数的使用(1)
数据表:OrderItems,表中数据如下:
| quantity |
|---|
| 10 |
| 100 |
| 1000 |
| 10001 |
| 2 |
| 15 |
【问题】编写 SQL 语句,确定已售出产品的总数。查询结果如下:
| items_ordered |
|---|
| 11128 |
表结构及数据如下:
/*
DROP TABLE IF EXISTS `OrderItems`;
CREATE TABLE IF NOT EXISTS `OrderItems`(
quantity INT(16) NOT NULL COMMENT '商品数量'
);
INSERT `OrderItems` VALUES (10),(100),(1000),(10001),(2),(15);
*/
解答:
mysql> select sum(quantity) items_ordered from OrderItems;
+---------------+
| items_ordered |
+---------------+
| 11128 |
+---------------+
1 row in set (0.00 sec)
60、聚合函数的使用(2)
数据表:OrderItems,表中数据如下:
| quantity | prod_id |
|---|---|
| 10 | AR01 |
| 100 | AR10 |
| 1000 | BR01 |
| 10001 | BR010 |
【问题】编写 SQL 语句,确定已售出产品项(prod_id)为 “BR01” 的总数。查询结果如下:
| items_ordered |
|---|
| 1000 |
表结构及数据如下:
/*
DROP TABLE IF EXISTS `OrderItems`;
CREATE TABLE IF NOT EXISTS `OrderItems`(
quantity INT(16) NOT NULL COMMENT '商品数量',
prod_id VARCHAR(255) NOT NULL COMMENT '商品项'
);
INSERT `OrderItems` VALUES (10,'AR01'),(100,'AR10'),(1000,'BR01'),(10001,'BR010');
*/
解答:
mysql> select sum(quantity) items_ordered from OrderItems where prod_id = 'BR01';
+---------------+
| items_ordered |
+---------------+
| 1000 |
+---------------+
1 row in set (0.01 sec)
61、聚合函数的使用(3)
数据表:Products,表中数据如下:
| prod_price |
|---|
| 9.49 |
| 600 |
| 1000 |
【问题】编写 SQL 语句,确定 Products 表中价格不超过 10 元的最贵产品的价格(prod_price)。查询结果如下:
| max_price |
|---|
| 9.49 |
表结构及数据如下:
/*
DROP TABLE IF EXISTS `Products`;
CREATE TABLE IF NOT EXISTS `Products` (
`prod_price` DOUBLE NOT NULL COMMENT '产品价格'
);
INSERT INTO `Products` VALUES (9.49),
(600),
(1000);
*/
解答:
mysql> select max(prod_price) max_price from Products where prod_price <= 10;
+-----------+
| max_price |
+-----------+
| 9.49 |
+-----------+
1 row in set (0.00 sec)