/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);
