MySQL单表查询常见操作实例总结

本文实例总结了mysql单表查询常见操作。分享给大家供大家参考，具体如下：

创建fruits表：

create table fruits
(
 f_id  char(10)   not null,
 s_id  int not null,
 f_name char(255)   not null,
 f_price decimal(8,2) not null,
 primary key(f_id)
) ;
insert into fruits (f_id, s_id, f_name, f_price)
values('a1', 101,'apple',5.2),
('b1',101,'blackberry', 10.2),
('bs1',102,'orange', 11.2),
('bs2',105,'melon',8.2),
('t1',102,'banana', 10.3),
('t2',102,'grape', 5.3),
('o2',103,'coconut', 9.2),
('c0',101,'cherry', 3.2),
('a2',103, 'apricot',2.2),
('l2',104,'lemon', 6.4),
('b2',104,'berry', 7.6),
('m1',106,'mango', 15.6),
('m2',105,'xbabay', 2.6),
('t4',107,'xbababa', 3.6),
('m3',105,'xxtt', 11.6),
('b5',107,'xxxx', 3.6);

常用查询：

select * from fruits;
select f_name,f_price from fruits;
select f_name,f_price from fruits where f_price=10.2;
select f_name,f_price from fruits where f_price<10;
select * from fruits where s_id in (101,102) order by f_name;
select * from fruits where s_id not in (101,102) order by f_name;
select f_name,f_price from fruits where f_price between 2.00 and 10.20;
select f_name,f_price from fruits where f_price not between 2.00 and 10.20;
select f_name,f_price from fruits where f_name like "b%";
select f_name,f_price from fruits where f_name like "%g%";
select f_name,f_price from fruits where f_name like "b%y";
select f_name,f_price from fruits where f_name like "____y";

创建customers表：

create table customers
(
 c_id   int    not null auto_increment,
 c_name  char(50) not null,
 c_address char(50) null,
 c_city  char(50) null,
 c_zip   char(10) null,
 c_contact char(50) null,
 c_email  char(255) null,
 primary key (c_id)
);
insert into customers(c_id, c_name, c_address, c_city, c_zip, c_contact, c_email)
values(10001, 'redhook', '200 street ', 'tianjin', '300000', 'liming', '[e-mail]'),
(10002, 'stars', '333 fromage lane', 'dalian', '116000', 'zhangbo','[e-mail]'),
(10003, 'netbhood', '1 sunny place', 'qingdao', '266000', 'luocong', null),
(10004, 'joto', '829 riverside drive', 'haikou', '570000', 'yangshan', '[e-mail]');

常用查询语句：

select c_id,c_name,c_email from customers where c_email is null;
select c_id,c_name,c_email from customers where c_email is not null;
select f_name,f_price from fruits where s_id=101 and f_price>=5;
select f_name,f_price from fruits where s_id in (101,102) and f_price >=5 and f_name="apple";
select f_name,f_price from fruits where s_id=101 or s_id=102;

使用in操作更加简洁明了

select f_name,f_price
from fruits
where s_id in (101 ,102);

字段不重复

select distinct s_id from fruits;
select f_name from fruits order by f_name;

如果第一列数据中没有相同值，将不再对第二列进行排序。

select f_name, f_price
from fruits
order by f_name, f_price;

按价格降序排列,desc为降序，默认为升序。

select f_name, f_price from fruits order by f_price desc;
select f_name, f_price from fruits order by f_price desc,f_name;
select s_id, count(*) as total from fruits group by s_id;
select s_id, group_concat(f_name) as names from fruits group by s_id;

使用having过滤分组

select s_id, group_concat(f_name) as names
from fruits
group by s_id having count(f_name)>1;

在group by 子句中使用with rollup

select s_id, count(*) as total from fruits group by s_id with rollup;
select * from fruits group by s_id,f_name;

创建orderitems表：

create table orderitems
(
 o_num   int     not null,
 o_item   int     not null,
 f_id    char(10)   not null,
 quantity  int     not null,
 item_price decimal(8,2) not null,
 primary key (o_num,o_item)
) ;
insert into orderitems(o_num, o_item, f_id, quantity, item_price)
values(30001, 1, 'a1', 10, 5.2),
(30001, 2, 'b2', 3, 7.6),
(30001, 3, 'bs1', 5, 11.2),
(30001, 4, 'bs2', 15, 9.2),
(30002, 1, 'b3', 2, 20.0),
(30003, 1, 'c0', 100, 10),
(30004, 1, 'o2', 50, 2.50),
(30005, 1, 'c0', 5, 10),
(30005, 2, 'b1', 10, 8.99),
(30005, 3, 'a2', 10, 2.2),
(30005, 4, 'm1', 5, 14.99);

常用查询语句：

select o_num, sum(quantity * item_price) as ordertotal
from orderitems
group by o_num
having sum(quantity*item_price) >= 100;
select o_num, sum(quantity * item_price) as ordertotal
from orderitems
group by o_num
having sum(quantity*item_price) >= 100
order by ordertotal;
select * from fruits limit 8;

从第五行开始，读取3行

select * from fruits limit 4,3;

【例.1】从fruits表中检索所有字段的数据

select * from fruits;
select f_id, s_id ,f_name, f_price from fruits;

【例.2】查询当前表中f_name列所有水果名称，输入如下语句：

select f_name from fruits;

【例.3】例如，从fruits表中获取f_name和f_price两列，输入如下语句：

select f_name, f_price from fruits;

【例.4】查询价格为10.2元的水果的名称，输入如下语句：

select f_name, f_price
from fruits
where f_price = 10.2;

【例.5】查找名称为“apple”的水果的价格,输入如下语句：

select f_name, f_price
from fruits
where f_name = 'apple';

【例.6】查询价格小于10的水果的名称，输入如下语句：

select f_name, f_price
from fruits
where f_price < 10;

【例.7】s_id为101和102的记录，输入如下语句：

select s_id,f_name, f_price
from fruits
where s_id in (101,102)
order by f_name;

【例.8】查询所有s_id不等于101也不等于102的记录，输入如下语句：

select s_id,f_name, f_price
from fruits
where s_id not in (101,102)
order by f_name;

【例.9】查询价格在2.00元到10.5元之间水果名称和价格

select f_name, f_price
from fruits
where f_price between 2.00 and 10.20;

【例.10】查询价格在2.00元到10.5元之外的水果名称和价格

select f_name, f_price
from fruits
where f_price not between 2.00 and 10.20;

【例.11】查找所有以‘b'字母开头的水果，输入如下语句：

select f_id, f_name
from fruits
where f_name like 'b%';

【例.12】在fruits表中，查询f_name中包含字母‘g'的记录

select f_id, f_name
from fruits
where f_name like '%g%';

【例.13】查询以‘b'开头，并以‘y'结尾的水果的名称

select f_name
from fruits
where f_name like 'b%y';

【例7.14】在fruits表中，查询以字母‘y'结尾，且‘y'前面只有4个字母的记录

select f_id, f_name
from fruits
where f_name like '____y';

【例.15】查询customers表中c_email为空的记录的c_id、c_name和c_email字段值：

select c_id, c_name,c_email
from customers
where c_email is null;

【例.16】查询customers表中c_email不为空的记录的c_id、c_name和c_email字段值

select c_id, c_name,c_email
from customers
where c_email is not null;

【例.17】在fruits表中查询s_id = ‘101'，并且f_price大于5的记录价格和名称

select f_id, f_price, f_name
from fruits
where s_id = '101' and f_price >=5;

【例.18】在fruits表中查询s_id = ‘101'或者'102'，并且f_price大于5，并且f_name='apple'的记录价格和名称

select f_id, f_price, f_name
from fruits
where s_id in('101', '102') and f_price >= 5 and f_name = 'apple';

【例.19】查询s_id=101或者s_id=102的水果供应商的f_price和f_name，sql语句如下：

select s_id,f_name, f_price
from fruits
where s_id = 101 or s_id = 102;

【例.20】查询s_id=101或者s_id=102的水果供应商的f_price和f_name

select s_id,f_name, f_price
from fruits
where s_id in(101,102);

【例.21】查询fruits表中s_id字段的值，并返回s_id字段值不得重复

select distinct s_id from fruits;

【例.22】查询fruits表的f_name字段值，并对其进行排序

select f_name from fruits order by f_name;

【例.23】查询fruits表中的f_name和f_price字段，先按f_name排序，再按f_price排序

select f_name, f_price
from fruits
order by f_name, f_price;

【例.24】查询fruits表中的f_name和f_price字段，对结果按f_price降序方式排序

select f_name, f_price
from fruits
order by f_price desc;

【例.25】查询fruits表，先按f_price降序排序，再按f_name字段升序排序，sql语句如下：

select f_price, f_name
from fruits
order by f_price desc, f_name;

【例.26】根据s_id对fruits表中的数据进行分组

select s_id, count(*) as total
from fruits
group by s_id;

【例.27】根据s_id对fruits表中的数据进行分组，将每个供应商的水果名称显示出来

select s_id, group_concat(f_name) as names
from fruits
group by s_id;

【例.28】根据s_id对fruits表中的数据进行分组，并显示水果种类大于1的分组信息

select s_id, group_concat(f_name) as names
from fruits
group by s_id having count(f_name) > 1;

【例.29】根据s_id对fruits表中的数据进行分组，并显示记录数量

select s_id, count(*) as total
from fruits
group by s_id with rollup;

【例.30】根据s_id和f_name字段对fruits表中的数据进行分组， sql语句如下，

select * from fruits group by s_id,f_name;

【例.31】查询订单价格大于100的订单号和总订单价格

select o_num, sum(quantity * item_price) as ordertotal
from orderitems
group by o_num
having sum(quantity*item_price) >= 100;

【例.32】显示fruits表查询结果的前4行，输入如下语句：

select * from fruits limit 4;

【例.33】在fruits 表中，使用limit子句，返回从第5个记录开始的，行数长度为3的记录

select * from fruits limit 4, 3;

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