/*增*/?
INSERT INTO students (name,age) VALUES ("神奇美",18) /*插入數(shù)據(jù)*/
/*刪*/?
DELETE FROM students WHERE id = 5 AND NAME = "神奇美"? /*刪除數(shù)據(jù)并沒有刪除id*/
/*改*/?
UPDATE students SET sex = "女" WHERE id = 5 /*更新數(shù)據(jù)*/
/*查*/?
SELECT * FROM students ORDER BY age DESC? /*查詢學生表年兩由大到小降序排列 反之ASC是升序*/
SELECT * FROM students ORDER BY age ASC
SELECT * FROM students GROUP BY sex /*根據(jù)性別分組*/
SELECT name FROM students /*查詢n所有name*/
SELECT * FROM students WHERE sex = "男" /*查詢表中條件性別為男的數(shù)據(jù)*/
SELECT COUNT(1) from students /*統(tǒng)計表中有多少條數(shù)據(jù)*/
SELECT COUNT(1) from students WHERE sex = "女" /*統(tǒng)計表中性別為女的條數(shù)數(shù)據(jù)*/
/*創(chuàng)建表*/
CREATE TABLE techer (
id INT(11) NOT NULL PRIMARY KEY auto_increment, #id 整形 不能為空 主鍵 自動遞增
name VARCHAR(255)
)
