轉自：http://www.cnblogs.com/myqiao/archive/2011/07/13/2105800.html
一、插入數據 INSERT INTO 表（列...） VALUES（值...）
根據前面幾篇的內容，我們可以很輕送的創建一個數據表，並向其中插入一些數據，不多說，看例子：
myqiao@ubuntu:~/My Documents/db$ sqlite3 test.db -- Loading resources from /home/myqiao/.sqliterc SQLite version 3.7.4 Enter ".help" for instructions Enter SQL statements terminated with a ";" sqlite> .tables sqlite> sqlite> CREATE TABLE Teachers( ...> Id integer PRIMARY KEY, ...> Name text NOT NULL, ...> Age integer CHECK(Age>22), ...> Country text DEFAULT 'USA'); sqlite> .tables Teachers sqlite> sqlite> INSERT INTO Teachers VALUES(1,'Alice',25,'CHN'); sqlite> INSERT INTO Teachers VALUES(2,'Bob',25,'BRA'); sqlite> INSERT INTO Teachers(Id,Name,Age,Country) VALUES(3,'Charls',33,'USA'); sqlite> INSERT INTO Teachers(Name,Age) VALUES('Jhon',43); sqlite> SELECT * FROM Teachers; Id Name Age Country ---- --------------- --------------- --------------- 1 Alice 25 CHN 2 Bob 25 BRA 3 Charls 33 USA 4 Jhon 43 USA sqlite>
很簡單，創建了一個 Teachers 表並向其中添加了四條數據，設定了一些約束，其中有自動增加的主鍵、默認值等等。
二、修改數據 UPDATE 表 SET 列 = '新值' 【WHERE 條件語句】
UPDATE 語句用來更新表中的某個列，如果不設定條件，則所有記錄的這一列都被更新； 如果設定了條件，則符合條件的記錄的這一列被更新， WHERE 子句被用來設定條件，如下例：
sqlite> sqlite> SELECT * FROM Teachers; Id Name Age Country ---- --------------- --------------- --------------- 1 Alice 25 CHN 2 Bob 25 BRA 3 Charls 33 USA 4 Jhon 43 USA sqlite> sqlite> sqlite> UPDATE Teachers SET Country='China'; sqlite> SELECT * FROM Teachers; Id Name Age Country ---- --------------- --------------- --------------- 1 Alice 25 China 2 Bob 25 China 3 Charls 33 China 4 Jhon 43 China sqlite> sqlite> sqlite> UPDATE Teachers SET Country='America' WHERE Id=3; sqlite> SELECT * FROM Teachers; Id Name Age Country ---- --------------- --------------- --------------- 1 Alice 25 China 2 Bob 25 China 3 Charls 33 America 4 Jhon 43 China sqlite> sqlite> sqlite> UPDATE Teachers SET Country='India' WHERE Age<30; sqlite> SELECT * FROM Teachers; Id Name Age Country ---- --------------- --------------- --------------- 1 Alice 25 India 2 Bob 25 India 3 Charls 33 America 4 Jhon 43 China sqlite>
三、刪除數據 DELETE FROM 表 【WHERE 條件語句】
如果設定 WHERE 條件子句，則刪除符合條件的數據記錄；如果沒有設定條件語句，則刪除所有記錄
sqlite> sqlite> SELECT * FROM Teachers; Id Name Age Country ---- --------------- --------------- --------------- 1 Alice 25 India 2 Bob 25 India 3 Charls 33 America 4 Jhon 43 China sqlite> sqlite> sqlite> DELETE FROM Teachers WHERE Age>30; sqlite> SELECT * FROM Teachers; Id Name Age Country ---- --------------- --------------- --------------- 1 Alice 25 India 2 Bob 25 India sqlite> sqlite> sqlite> DELETE FROM Teachers; sqlite> SELECT * FROM Teachers; sqlite>
四、查找數據 SELECT 列... FROM 表
爲了後面的練習，需要一些樣本數據。 首先將下面的 SQL 語句保存到 data.sql 文件中
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;
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;
然後在在終端執行命令 .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>
五、 限制返回數量 SELECT 列... FROM 表 LIMIT 數量 OFFSET 位置
有時候數據庫中的數據太多，全部返回可不行，可以限制返回的數量，還可以設定返回的起始位置，如下：
sqlite> sqlite> SELECT * FROM Cars LIMIT 4; Id Name Cost ---- --------------- --------------- 1 Audi 52642 2 Mercedes 57127 3 Skoda 9000 4 Volvo 29000 sqlite> sqlite> SELECT * FROM Cars LIMIT 4 OFFSET 2; Id Name Cost ---- --------------- --------------- 3 Skoda 9000 4 Volvo 29000 5 Bentley 350000 6 Citroen 21000 sqlite>
六、 別名 SELECT 列 AS 別名，列 AS 別名 FROM
我們可以給返回數據集中的某些列起一個比較直觀的名字，比如把 Cost 改爲"Price Of Car"
sqlite> sqlite> SELECT Name , Cost AS 'Price Of Car' FROM Cars; Name Price Of Car ---- --------------- Audi 52642 Merc 57127 Skod 9000 Volv 29000 Bent 350000 Citr 21000 Humm 41400 Volk 21600 sqlite>
七、 條件查詢 SELECT 列 FROM 表 【WHERE 條件語句】
一般的條件語句都是大於、小於、等於之類的，這裏有幾個特別的條件語句
LIKE
- LIKE 用通配符匹配字符串
- 下劃線 _ 匹配一個字符串
- 百分號 % 匹配多個字符串
- LIKE 匹配字符串時不區分大小寫
sqlite> sqlite> SELECT * FROM Cars WHERE Name Like '____'; Id Name Cost ---- --------------- --------------- 1 Audi 52642 sqlite> sqlite> SELECT * FROM Cars WHERE Name Like '%en'; Id Name Cost ---- --------------- --------------- 6 Citroen 21000 8 Volkswagen 21600 sqlite> sqlite> SELECT * FROM Cars WHERE Name Like '%EN'; Id Name Cost ---- --------------- --------------- 6 Citroen 21000 8 Volkswagen 21600 sqlite>
GLOB
- GLOB 用通配符匹配字符串
- 下劃線 ? 匹配一個字符串
- 百分號 * 匹配多個字符串
- LIKE 匹配字符串時,區分大小寫
BETWEEN 值1 AND 值2
返回兩個值之間的數據集合。下面的語句查詢價格在 20000 到 55000 之間的車，都是好車啊。
sqlite> sqlite> SELECT * FROM Cars WHERE Cost BETWEEN 20000 AND 55000; Id Name Cost ---- --------------- --------------- 1 Audi 52642 4 Volvo 29000 6 Citroen 21000 7 Hummer 41400 8 Volkswagen 21600 sqlite>
IN （集合）
對應列的值必須在集合中。下面的語句查找奧迪和悍馬的價格。
sqlite> sqlite> SELECT * FROM Cars WHERE Name IN ('Audi','Hummer'); Id Name Cost ---- --------------- --------------- 1 Audi 52642 7 Hummer 41400 sqlite>
八、 排序 ORDER BY 列 ASC (DESC)
指定某個列進行排序，ASC 爲升序，DESC 爲降序。下面的語句查詢汽車品牌和價格，並以價格排序
sqlite> sqlite> SELECT Name, Cost FROM Cars ORDER BY Cost DESC; Name Cost ---- --------------- Bent 350000 Merc 57127 Audi 52642 Humm 41400 Volv 29000 Volk 21600 Citr 21000 Skod 9000 sqlite>
九、 區分 DISTINCT 列
有一些字段的值可能會出現重複，比如訂單表中，一個客戶可能會有好幾份訂單，因此客戶的名字會重複出現。
到底有哪些客戶下了訂單呢？下面的語句將客戶名字區分出來。
sqlite> 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> sqlite> SELECT DISTINCT Customer FROM ORDERS; Customer --------------- Black Brown Robertson Smith Williamson sqlite>
十、 分組 GROUP BY 列
分組和前面的區分有一點類似。區分僅僅是爲了去掉重複項，而分組是爲了對各類不同項進行統計計算。
比如上面的例子，我們區分出 5 個客戶，這 5 個客戶一共下了 11 個訂單，說明很多客戶都下了不止一個訂單。
下面的語句統計每個客戶在訂單上總共花費了多少錢。
sqlite> sqlite> SELECT sum(OrderPrice) AS Total, Customer FROM Orders GROUP BY Customer; Total Customer --------------- --------------- 440 Black 860 Brown 340 Robertson 2040 Smith 1250 Williamson sqlite>
這裏 Sum 是 SQLite 內置的統計函數，在這個例子中用來求每個顧客的訂單價格的和。
統計結果也可以設定返回條件，但是不能用 WHERE 子句，而是用 HAVING 子句，如下例，返回訂單總額大於 1000 的顧客。
sqlite> sqlite> SELECT sum(OrderPrice) AS Total, Customer FROM Orders ...> GROUP BY Customer HAVING sum(OrderPrice)>1000; Total Customer --------------- --------------- 2040 Smith 1250 Williamson sqlite>
十一、 邏輯運算符
有的查詢涉及的條件語句很複雜，是有好幾個條件語句經過邏輯運算得來的，一共有三種邏輯運算符：
- AND
- OR
- NOT