主要有下面几个函数:
所有函数都是大小写不敏感。欲了解更多详情,请查看 SQLite 的官方文档。
(1)count() : 计算表中的行数
(2)MAX() : 求某列的最大值
(3)MIN():求某列的最小值
(4)sqlite_version():返回SQLite的版本
(5)AVG():求某列的平均值
(6)SUM():求某列的和
(7)RNDOM():产生随机数
(8)ABS():求绝对值
(9)upper():字符串转成大写
(10)lower():字符串转成小写
(11)length():求字符串的长度
实例:
select count(*) from company;
select MAX(SALARY), NAME from company;
select MIN(SALARY), NAME from company;
select MIN(SALARY), NAME from company;
select SUM(SALARY) from company;
select random() as Random;
select ABS(5), ABS(-5), ABS(NULL), ABS('aa');
select upper(NAME) as Big_Name from company;
select lower(NAME) as Small_Name from company;
select length(NAME) as Name_len , name from company;
select sqlite_version() as SQL_VER;
1. 请运行上面的例子并分析。