Bài 14: Một số hàm thông dụng trong SQLite - Học SQLite cơ bản

ID          NAME        AGE         ADDRESS     SALARY----------  ----------  ----------  ----------  ----------1           Paul        32          California  20000.02           Allen       25          Texas       15000.03           Teddy       23          Norway      20000.04           Mark        25          Rich-Mond   65000.05           David       27          Texas       85000.06           Kim         22          South-Hall  45000.07           James       24          Houston     10000.0

1. Hàm COUNT trong SQLite

sqlite> SELECT count(*) FROM COMPANY;

count(*)----------7

2. Hàm MAX trong SQLite

sqlite> SELECT max(salary) FROM COMPANY;

max(salary)-----------85000.0

3. Hàm MIN trong SQLite

sqlite> SELECT min(salary) FROM COMPANY;

min(salary)-----------10000.0

4. Hàm AVG trong SQLite

sqlite> SELECT avg(salary) FROM COMPANY;

avg(salary)----------------37142.8571428572

5. Hàm SUM trong SQLite

sqlite> SELECT sum(salary) FROM COMPANY;

sum(salary)-----------260000.0

6. Hàm RANDOM trong SQLite

sqlite> SELECT random() AS Random;

Random-------------------5876796417670984050

7. Hàm ABS trong SQLite

sqlite> SELECT abs(5), abs(-15), abs(NULL), abs(0), abs("ABC");

abs(5)      abs(-15)    abs(NULL)   abs(0)      abs("ABC")----------  ----------  ----------  ----------  ----------5           15                      0           0.0

8. Hàm UPPER trong SQLite

sqlite> SELECT upper(name) FROM COMPANY;

upper(name)-----------PAULALLENTEDDYMARKDAVIDKIMJAMES

9. Hàm LOWER trong SQLite

sqlite> SELECT lower(name) FROM COMPANY;

lower(name)-----------paulallenteddymarkdavidkimjames

10. Hàm LENGTH trong SQLite

sqlite> SELECT name, length(name) FROM COMPANY;

NAME        length(name)----------  ------------Paul        4Allen       5Teddy       5Mark        4David       5Kim         3James       5

11. Hàm sqlite_version trong SQLite

sqlite> SELECT sqlite_version() AS 'SQLite Version';

SQLite Version--------------3.6.20