一個SQLite數據庫查詢數據的代碼實例
作者:左洸
本文主要介紹了SQLite數據庫查詢數據的一個實例,通過這個實例讓我們來更進一步地了解SQLite數據庫的查詢。
我們知道,在SQL Server數據庫中查詢數據時需要用到SELECT……FROM語句結合WHERE條件來實現的,其實SQLite數據庫查詢數據的方式也是這樣的,本文通過一個實例來介紹這一過程,希望能給大家帶來收獲。
首先將下面的SQL 語句保存到 data.sql 文件中(為了以后的練習使用):
- BEGIN TRANSACTION;
- CREATE TABLE Cars(Id integer PRIMARY KEY, Name text, Cost integer);
- INSERT INTO Cars VALUES(1,'Audi',52642);
- INSERT INTO Cars VALUES(2,'Mercedes',57127);
- INSERT INTO Cars VALUES(3,'Skoda',9000);
- INSERT INTO Cars VALUES(4,'Volvo',29000);
- INSERT INTO Cars VALUES(5,'Bentley',350000);
- INSERT INTO Cars VALUES(6,'Citroen',21000);
- INSERT INTO Cars VALUES(7,'Hummer',41400);
- INSERT INTO Cars VALUES(8,'Volkswagen',21600);
- COMMIT;
- BEGIN TRANSACTION;
- CREATE TABLE Orders(Id integer PRIMARY KEY, OrderPrice integer CHECK(OrderPrice>0),
- Customer text);
- INSERT INTO Orders(OrderPrice, Customer) VALUES(1200, "Williamson");
- INSERT INTO Orders(OrderPrice, Customer) VALUES(200, "Robertson");
- INSERT INTO Orders(OrderPrice, Customer) VALUES(40, "Robertson");
- INSERT INTO Orders(OrderPrice, Customer) VALUES(1640, "Smith");
- INSERT INTO Orders(OrderPrice, Customer) VALUES(100, "Robertson");
- INSERT INTO Orders(OrderPrice, Customer) VALUES(50, "Williamson");
- INSERT INTO Orders(OrderPrice, Customer) VALUES(150, "Smith");
- INSERT INTO Orders(OrderPrice, Customer) VALUES(250, "Smith");
- INSERT INTO Orders(OrderPrice, Customer) VALUES(840, "Brown");
- INSERT INTO Orders(OrderPrice, Customer) VALUES(440, "Black");
- INSERT INTO Orders(OrderPrice, Customer) VALUES(20, "Brown");
- COMMIT;
然后在在終端執行命令 .read data.sql,將數據導入到數據庫中:
- sqlite>
- sqlite> .tables
- Friends
- sqlite> .read data.sql
- sqlite> .tables
- Cars Orders Teachers
- sqlite>
可以看到,Cars 表和 Orders 表已經導入到數據庫中,現在可以查詢了:
- sqlite>
- sqlite> SELECT * FROM Cars;
- Id Name Cost
- ---- --------------- ---------------
- 1 Audi 52642
- 2 Mercedes 57127
- 3 Skoda 9000
- 4 Volvo 29000
- 5 Bentley 350000
- 6 Citroen 21000
- 7 Hummer 41400
- 8 Volkswagen 21600
- sqlite> SELECT * FROM Orders;
- Id OrderPrice Customer
- ---- --------------- ---------------
- 1 1200 Williamson
- 2 200 Robertson
- 3 40 Robertson
- 4 1640 Smith
- 5 100 Robertson
- 6 50 Williamson
- 7 150 Smith
- 8 250 Smith
- 9 840 Brown
- 10 440 Black
- 11 20 Brown
- sqlite>
關于SQLite數據庫查找數據的知識就介紹到這里,我們還會在以后的文章里繼續介紹,謝謝各位一直以來的支持!
【編輯推薦】
責任編輯:趙鵬
來源:
博客園