uston 10000.0
3 Teddy 23 Norway 20000.0
6 Kim 22 South-Hall 45000.0
//
sqlite> SELECT * FROM COMPANY WHERE AGE > (SELECT AGE FROM COMPANY WHERE SALARY > 65000);
ID NAME AGE ADDRESS SALARY
1 Paul 32 California 20000.0
sqlite> SELECT * FROM COMPANY WHERE AGE < (SELECT AGE FROM COMPANY WHERE SALARY > 65000);
ID NAME AGE ADDRESS SALARY
7 James 24 Houston 10000.0
2 Allen 25 Texas 15000.0
3 Teddy 23 Norway 20000.0
4 Mark 25 Rich-Mond 65000.0
6 Kim 22 South-Hall 45000.0
4.6.4 排序、分组、去重、时间
//通过内置函数查看一共有多少条数据
sqlite> SELECT COUNT(*) AS "RECORDS" FROM COMPANY;
RECORDS
7
//显示前4条
sqlite> SELECT * FROM COMPANY LIMIT 4;
ID NAME AGE ADDRESS SALARY
1 Paul 32 California 20000.0
7 James 24 Houston 10000.0
2 Allen 25 Texas 15000.0
3 Teddy 23 Norway 20000.0
//按SALARY降序排序
sqlite> SELECT * FROM COMPANY ORDER BY SALARY ASC;
ID NAME AGE ADDRESS SALARY
7 James 24 Houston 10000.0
2 Allen 25 Texas 15000.0
1 Paul 32 California 20000.0
3 Teddy 23 Norway 20000.0
6 Kim 22 South-Hall 45000.0
4 Mark 25 Rich-Mond 65000.0
5 David 27 Texas 85000.0
//按SALARY升序排序
sqlite> SELECT * FROM COMPANY ORDER BY SALARY DESC;
ID NAME AGE ADDRESS SALARY
5 David 27 Texas 85000.0
4 Mark 25 Rich-Mond 65000.0
6 Kim 22 South-Hall 45000.0
1 Paul 32 California 20000.0
3 Teddy 23 Norway 20000.0
2 Allen 25 Texas 15000.0
7 James 24 Houston 10000.0
//按NAME和SALARY升序排序
sqlite> SELECT * FROM COMPANY ORDER BY AGE,SALARY DESC;
ID NAME AGE ADDRESS SALARY
6 Kim 22 South-Hall 45000.0
3 Teddy 23 Norway 20000.0
7 James 24 Houston 10000.0
4 Mark 25 Rich-Mond 65000.0
2 Allen 25 Texas 15000.0
5 David 27 Texas 85000.0
1 Paul 32 California 20000.0
// GROUP BY 子句用于与 SELECT 语句一起使用，来对相同的数据进行分组。
// 查询某个人的工资总数
sqlite>
SELECT NAME, SUM(SALARY) FROM COMPANY GROUP BY NAME;
NAME SUM(SALARY)
Allen 15000.0
David 85000.0
James 10000.0
Kim 45000.0
Mark 65000.0
Paul 20000.0
Teddy 20000.0
// GROUP BY 和 ORDER BY一起用
sqlite> SELECT NAME, SUM(SALARY) FROM COMPANY GROUP BY NAME ORDER BY NAME DESC;
NAME SUM(SALARY)
Teddy 20000.0
Paul 20000.0
Mark 65000.0
Kim 45000.0
James 10000.0
David 85000.0
Allen 15000.0
//HAVING 子句允许指定条件来过滤将出现在最终结果中的分组结果。
//WHERE 子句在所选列上设置条件，而 HAVING 子句则在由 GROUP BY 子句创建的分组上设置条件。
//在一个查询中，HAVING 子句必须放在 GROUP BY 子句之后，必须放在 ORDER BY 子句之前
//查询所有数据
qlite> SELECT * FROM COMPANY;
ID NAME AGE ADDRESS SALARY
1 Paul 32 California 20000.0
7 James 24 Houston 10000.0
2 Allen 25 Texas 15000.0
3 Teddy 23 Norway 20000.0
4 Mark 25 Rich-Mond 65000.0
5 David 27 Texas 85000.0
6 Kim 22 South-Hall 45000.0
//查询AGE，并去重
sqlite> SELECT DISTINCT AGE FROM COMPANY;
AGE
32
24
25
23
27
22
日期 & 时间
//把header关掉了
sqlite> . header off
sqlite> SELECT date('now');
2014-02-27
sqlite> SELECT datetime(1092941466, 'unixepoch');
2004-08-19 18:51:06
sqlite> SELECT TIME('NOW');
07:47:25?
4.6.5. 常用函数
//表行数
sqlite> SELECT count(*) FROM COMPANY;
7
//最大值
sqlite> SELECT max(salary) FROM COMPANY;
85000.0
//最小值
sqlite> SELECT min(salary) FROM COMPANY;
10000.0
//平均值
sqlite> SELECT avg(salary) FROM COMPANY;
37142.8571428572
sqlite> SELECT sum(salary) FROM COMPANY;
260000.0
//转大写
sqlite> SELECT upper(name) FROM COMPANY;
PAUL
JAMES
ALLEN
TEDDY
MARK
DAVID
KIM
//转小写
sqlite> SELECT lower(name) FROM COMPANY;
paul
james
allen
teddy
mark
david
kim
//长度
sqlite> SELECT name, length(name) FR