/*简单约束*/
CREATE TABLE IF NOT EXISTS t_student(id INTEGER PRIMARY KEY AUTOINCREMENT, name TEXT, age INTEGER);
CREATE TABLE IF NOT EXISTS t_student(id INTEGER PRIMARY KEY AUTOINCREMENT, name TEXT NOT NULL, age INTEGER NOT NULL);
CREATE TABLE IF NOT EXISTS t_student(id INTEGER PRIMARY KEY AUTOINCREMENT, name TEXT UNIQUE, age INTEGER);
CREATE TABLE IF NOT EXISTS t_student(id INTEGER PRIMARY KEY AUTOINCREMENT, name TEXT, age INTEGER DEFAULT 1);/*分页*/
SELECT * FROM t_student ORDER BY id ASC LIMIT 30, 10;/*排序*/
SELECT * FROM t_student WHERE score > 50 ORDER BY age DESC;
SELECT * FROM t_student WHERE score < 50 ORDER BY age ASC , score DESC;/*计量*/
SELECT COUNT(*) FROM t_student WHERE age > 50;/*别名*/
SELECT name as myName, age as myAge, score as myScore FROM t_student;
SELECT name myName, age myAge, score myScore FROM t_student;
SELECT s.name myName, s.age myAge, s.score myScore FROM t_student s WHERE s.age > 50;/*查询*/
SELECT name, age, score FROM t_student;
SELECT * FROM t_student;/*修改指定数据*/
UPDATE t_student SET name = 'MM' WHERE age = 10;
UPDATE t_student SET name = 'WW' WHERE age is 7;
UPDATE t_student SET name = 'XXOO' WHERE age < 20;
UPDATE t_student SET name = 'NNMM' WHERE age < 50 and score > 10;/*删除数据*/
DELETE FROM t_student;/*更新数据*/
UPDATE t_student SET name = 'LNJ';/*插入数据*/INSERT INTO t_student(age, score, name) VALUES ('28', 100, 'jonathan');INSERT INTO t_student(name, age) VALUES ('lee', '28');INSERT INTO t_student(score) VALUES (100);/*插入数据*/
INSERT INTO t_student(name, age, score) VALUES ('lee', '28', 100);/*添加主键*/
CREATE TABLE IF NOT EXISTS t_student (id INTEGER PRIMARY KEY AUTOINCREMENT, name TEXT, age INTEGER, score REAL);
/*添加主键*/
CREATE TABLE IF NOT EXISTS t_student (id INTEGER, name TEXT, age INTEGER, score REAL, PRIMARY KEY(id));/*删除表*/
DROP TABLE IF EXISTS t_student;/*创建表*/
CREATE TABLE IF NOT EXISTS t_student(id INTEGER , name TEXT, age , score REAL);

1.打开数据库
int sqlite3_open(const char *filename,   // 数据库的文件路径sqlite3 **ppDb          // 数据库实例
);2.执行任何SQL语句
int sqlite3_exec(sqlite3*,                                  // 一个打开的数据库实例const char *sql,                           // 需要执行的SQL语句int (*callback)(void*,int,char**,char**),  // SQL语句执行完毕后的回调void *,                                    // 回调函数的第1个参数char **errmsg                              // 错误信息
);3.检查SQL语句的合法性（查询前的准备）
int sqlite3_prepare_v2(sqlite3 *db,            // 数据库实例const char *zSql,       // 需要检查的SQL语句int nByte,              // SQL语句的最大字节长度sqlite3_stmt **ppStmt,  // sqlite3_stmt实例，用来获得数据库数据const char **pzTail
);4.查询一行数据
int sqlite3_step(sqlite3_stmt*); // 如果查询到一行数据，就会返回SQLITE_ROW5.利用stmt获得某一字段的值（字段的下标从0开始）
double sqlite3_column_double(sqlite3_stmt*, int iCol);  // 浮点数据
int sqlite3_column_int(sqlite3_stmt*, int iCol); // 整型数据
sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol); // 长整型数据
const void *sqlite3_column_blob(sqlite3_stmt*, int iCol); // 二进制文本数据
const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol);  // 字符串数据