Bài 9: Select - Truy vấn dữ liệu trong SQLite - Học SQLite cơ bản

1. Cú pháp

SELECT column1, column2, columnN FROM table_name;

SELECT * FROM table_name;

2. Ví dụ:

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

sqlite> .header onsqlite> .mode columnsqlite> SELECT * FROM COMPANY;

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

3. Thiết lập chiều rộng cột đầu ra (Output Column)

sqlite> .width 10, 20, 10sqlite> SELECT * FROM COMPANY;

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

4. Thông tin lược đồ (Schema)

sqlite> SELECT tbl_name FROM sqlite_master WHERE type = 'table';

tbl_name----------COMPANY

sqlite> SELECT sql FROM sqlite_master WHERE type = 'table' AND tbl_name = 'COMPANY';

CREATE TABLE COMPANY(   ID INT PRIMARY KEY     NOT NULL,   NAME           TEXT    NOT NULL,   AGE            INT     NOT NULL,   ADDRESS        CHAR(50),   SALARY         REAL)