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PHP之Mysql常用SQL语句示例的深入分析

程序员文章站 2024-02-23 15:10:34
1.插入数据insert into表名(列名1,列名2,列名..) values(值1,值2,值...);  insert into product(name...
1.插入数据
insert into表名(列名1,列名2,列名..) values(值1,2,值...); 
insert into product(name, price, pic_path) values('nike',500,'uploads/3245.jpg');

2.更新数据
update 表名set列名1=值1,列名2=值2[where条件]; 
update product set name='lining', price=50where id=2; 

3.删除数据
deletefrom表名[where条件]; 
deletefrom product where id=2;

4.查询所有数据 
select*from表名;select*from product;

5.查询部份列
select列名1,列名2,列名n from表名;
select name, price from product;

6.条件查询
# 比较 =, <, >, <=, >=, !=
select*from表名where列名=值;
select*from product where id=2;
# and 与 
select*from表名where条件1and条件2and条件n; 
select*from product where name='nike'and price=50;
# or 或 
select*from表名where条件1or条件2or条件n;
select*from product where name='nike'or price>50; 
# not 非 
select*from表名wherenot条件1;
select*from product wherenot name='nike'; 
#in 枚举 
select*from表名where列名in(值1,2,n); 
select*from product where id in(2,3,4,10); 
select*from product where id notin(2,3,4,10); 
#like 模糊查询 
select*from表名where列名 like '%值%'; 
select*from product where name like '%li%'; 
#between...and... 范围查询 
select*from表名where列名 between and值; 
select*from order where created between '2010-01-01'and'2011-01-01';

7.查询排序
select*from表名 order by列名排序方式;
#排序方式: asc(升序,默认),desc(降序) 
select*from product order by created desc;

8.限制查询结果数量
select*from表名 limit 开始记录数,结果数量;select*from product limit 5;
select*from product limit 2,5;

9.聚合函数
# count 总记录数 
select count(列名)from student; 
select count(id)from student; 
# sum 总共 
select sum(列名)from student; 
select sum(age)from student; 
# avg 平均值 
select avg(列名)from student;
select avg(age)as avg_age from student; 
# max 最大值 
select max(列名)from student; 
select max(age)from student; 
# min 最小值 
select min(列名)from student; 
select min(age)from student;

10.子查询
select name from student where age<(select avg(age)from student ); 
select*from product where id in(select id from order );

11.连接查询
select s.username as stu_name, t.name as te_name from student s, teacher t where s.teacher_id=t.id;