//联系人:石虎QQ: 1224614774昵称:嗡嘛呢叭咪哄
/*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 NOTNULL, age INTEGER NOTNULL);
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 DEFAULT1);
/*分页*/
SELECT * FROM t_student ORDER BY id ASC LIMIT30,10;
/*排序*/
SELECT * FROM t_student WHERE score >50ORDER BY age DESC;
SELECT * FROM t_student WHERE score <50ORDER 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 is7;
UPDATE t_student SET name ='XXOO'WHERE age <20;
UPDATE t_student SET name ='NNMM'WHERE age <50and score >10;
/*删除数据*/
DELETE FROM t_student;
/*更新数据*/
UPDATE t_student SET name ='gq';
/*插入数据*/
INSERT INTO t_student(name, age) VALUES('hml2',32);
INSERT INTO t_student(name) VALUES('hml2');
INSERT INTO t_student(age, name) VALUES(33,'hml3');
/*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));
/***********************DDL************************/
/*删除表*/
DROP TABLE IF EXISTS t_student;
DROP TABLE t_student;
/*创建表*/
CREATE TABLE IF NOT EXISTS t_student(name TEXT, age INTEGER, id INTEGER PRIMARY KEY AUTOINCREMENT);
CREATE TABLE t_student(name TEXT, age INTEGER, id INTEGER PRIMARY KEY AUTOINCREMENT);
CREATE TABLE t_student(name TEXT, age INTEGER, id INTEGER PRIMARY KEY);
CREATE TABLE t_student(name TEXT, age INTEGER, id INTEGER, PRIMARY KEY(id));
CREATE TABLE t_student(name TEXT, age INTEGER, id INTEGER );
