mysql 使用函数

字符串函数{
    1.upper
    2.lower
    3.length()
    4.left()
    5.right()
    6.rtrim()
    例如select upper(name) from info;//把名字换成大写展示
}
数学函数{
    avg();
    count();
    max();
    min();
    sum();
    例如select sum(age*age) from info;
    select min(id), max(id), sum(id), count(id) from info, avg(age);//汇总
}

字符串函数{

1.upper

2.lower

3.length()

4.left()

5.right()

6.rtrim()

例如select upper(name) from info;//把名字换成大写展示

}

数学函数{

avg();

count();

max();

min();

sum();

例如select sum(age*age) from info;

select min(id), max(id), sum(id), count(id) from info, avg(age);//汇总

}