/*增*/
INSERT INTO students (name,age) VALUES ("神奇美",18) /*插入数据*/
/*删*/
DELETE FROM students WHERE id = 5 AND NAME = "神奇美" /*删除数据并没有删除id*/
/*改*/
UPDATE students SET sex = "女" WHERE id = 5 /*更新数据*/
/*查*/
SELECT * FROM students ORDER BY age DESC /*查询学生表年两由大到小降序排列 反之ASC是升序*/
SELECT * FROM students ORDER BY age ASC
SELECT * FROM students GROUP BY sex /*根据性别分组*/
SELECT name FROM students /*查询n所有name*/
SELECT * FROM students WHERE sex = "男" /*查询表中条件性别为男的数据*/
SELECT COUNT(1) from students /*统计表中有多少条数据*/
SELECT COUNT(1) from students WHERE sex = "女" /*统计表中性别为女的条数数据*/
/*创建表*/
CREATE TABLE techer (
id INT(11) NOT NULL PRIMARY KEY auto_increment, #id 整形 不能为空 主键 自动递增
name VARCHAR(255)
)
