mysql的加密方式有种，以123456字符串来加密进行测试
1.MD5单项加密
数据类型：tinyblob
数据大小：32B
插入：INSERT INTO tb_user(username,PASSWORD,NAME,contact) VALUES('TEST',MD5('123456'),'TEST','1234565475')
查询：SELECT * FROM tb_user WHERE tb_user.password = MD5('123456')
2.PASSWORD单项加密
数据类型：tinyblob
数据大小：41B
插入：INSERT INTO tb_user(username,PASSWORD,NAME,contact) VALUES('TEST',PASSWORD('123456'),'TEST','1234565475')
查询：SELECT * FROM tb_user WHERE tb_user.password = PASSWORD('123456')
3.ENCODE 和 DECODE双向加密
INSERT INTO tb_user(username,PASSWORD,NAME,contact) VALUES('TEST',ENCODE('123456','1234'),'TEST','1234565475')
1234为加密关键字
SELECT DECODE((SELECT PASSWORD FROM tb_user WHERE id = 3),'1234')
可以查询到源密码
