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insert into 表名 values(default,"名字","2011-04-15 12:22:25"); //default可以换成null------------------------------insert into 表名 (name,datetime) values("名字","2011-04-15 12:22:25");使用SQL语法大写，增加可读性(小写部分就是自己数据库写的表/字段喽，具体你懂得...)。创建数据库：CREATE DATABASE mysql_db;删除数据库：DROP DATABASE mysql_db;查看数据库：SHOW DATABASES;使用数据库：USE mysql_db;查看数据库中的表:SHOW TABLES;创建表：CREATE TABLE user(id SMALLINT UNSIGNED PRIMARY KEY AUTO_INCREMENT,username VARCHAR(20) UNIQUE NOT NULL,sex ENUM('1','2','3') NOT NULL DEFAULT 3);查看表结构：①SELECT COLUMN FROM user;②DESC user;查看表创建语句(可查看各种自动生成的名字)：SHOW CREATE TABLE user;插入表记录：①INSERT INTO user(id,username,sex) VALUES(1,'Tom',1);②INSERT user(username) VALUES ('John');查找表：SELECT * FROM user;删除表中的数据(保留表结构)：TRUNCATE TABLE user;将查询结果写入新表:INSERT [INTO] privinces(sex) SELECT sex FROM user GROUP BY sex;(若表中有数据，请不要随意更改表名、列名)修改表名：①ALTER TABLE user RENAME [AS|TO] users;②RENAME TABLE user TO users;添加单列：ALTER TABLE userADD [COLUMN] age SMALLINT NOT NULL UNSIGNED DEFUALT 18[FIRST | AFTER sex];删除列：ALTER TABLE user DROP sex[,DROP age];修改列名称和定义：ALTER TABLE userCHANGE [COLUMN] age a_ge TINYINT NOT NULL UNSIGNED AFTER id;单表更新：UPDATE user SET age = age + 5,sex = 1 [WHERE id = 2];单表删除：DELETE FROM user [WHERE id =3];单(多)表连接：SELECT p.userid,p.username FROM user AS p LEFT JOIN user AS sON p.userid = s.age;单(多)表删除：DELETE * FROM user [AS] u1 LEFT JOIN (SELECT p.userid FROM user AS p LEFT JOIN user AS sON p.userid =s.age GROUP BY p.userid HAVING COUNT(s.age)>1 ) [AS] u2ON u1.userid = u2.ageWHERE u1.userid > u2.userid;查找记录：SELETE select_expr [,select_expr][FROM table_references[WHERE where_condition][GROUP BY {col_name|position}[ASC|DESC],...] //查询结果分组[HAVING where_condition] //设置分组条件[ORDER BY {col_name|expr|position}[ASC|DESC]] //对结果排序LIMIT {[offset,]row_count|row_count OFFSET offset}]//限制记录数量]记录为2、3行：SELECT * FROM user LIMIT 1,2;别名使用(在项目中一般都使用别名)AS alias_name:SELECT id AS uid FROM user AS u ;子查询：SELECT AVG(age) FROM user WHERE userid =[ALL|SOME|ANY|[NOT] IN|[NOT] EXISTS](SELECT uid FROM privinces WHERE pname = '河南');外键约束：(父表为user表,必须先在父表中插入数据，才能在子表中插入数据)CASEADE：从父表中删除或更新行 且 自动级联删除或更新子表中匹配的行；SET NULL:从父表删除或更新行，并设置子表中的外键列为NULL;RESTRICT:拒绝对父表的更新或删除操作；CREATE TABLE privinces(pid SMALLINT UNSIGNED PRIMARY KEY AUTO_INCREMENT,pname VARCHAR(20) NOT NULL ,uid SMALLINT,FOREIGN KEY (uid) REFERENCES user (id) //privinces的字段uid与user表的字段id外键约束ON DELETE CASEADE //删除时 级联删除);增加主键、唯一、外键约束：ALTER TABLE privincesADD [CONSTRAINT uq_pname] UNIQUE(pname);添加/删除默认约束：ALTER TABLE privincesALTER pname {SET DEFAULT literal | DROP DEFAULT};删除主键约束：ALTER TABLE privinces DROP PRIMARY KEY;删除唯一(索引)约束：(查看约束名字key_name: SHOW INDEXS FROM privinces;)ALTER TABLE privinces DROP {INDEX | KEY} 约束名;删除外键约束：(查看约束名字：SHOW CREATE TABLE privinces;)ALTER TABLE privinces DROP FOREIGN KEY 约束名;多表更新：UPDATE 表的参照关系 SET col_name = {[expr | value]};表的参照关系：tab1_reference {[INNER|CROSS] JOIN |{LEFT|RIGHT}[OUTER] JOIN} tab2_refenence ON conditional_expr;内连接：INNER JOIN左外连接：LEFT JOIN右外连接：ROGHT JOINUPDATE user INNER JOIN privinces ON user_privince = pnameSET user_privince = pid;//(更新user内连接privince,条件是user_privince.=pname,设置user_privince=pid)创建数据表的同时将查询结果写入数据表：CREATE TABLE table_name[create_definition, ...] //创建语句的定义select_statement; //要插入查询结果的 查询语句字符函数：CONCAT()字符连接；CONCAT('I','LOVE','YOU');CONCAT_WS()使用指定的分隔符进行字符连接；CONCAT_WS('|','A','B');第一个为分割符FORMAT();数字格式化;FORMAT(99999.99,1);将数字格式化，并保留1位小数LOWER();转换成小写字符UPPER();转换成大写字符LEFT();获取左侧字符RIGHT();获取右侧字符LENGTH();获取字符长度；LTRIN();删除前导字符；RTRIM();删除后续字符TRIM();删除前导、后续字符；SUBSTRING();字符串的截取；SUBSTRING('MYSQL',1,2);从第一位中截取2位；(mysql不允许为负值)[NOT] LIKE;模式匹配SELECT * FROM user WHERE username LIKE '%1%%' ESCAPE '1';REPLACE();替换字符串中的字符REPLACE('M??Y??SQL','?','*');将M??Y??SQL中的？替换成*;数值运算符：CEIL();进一去整；DIV;整数除法；FLOOR();舍一去整；MOD;取余数(模)；POWER();幂运算；ROUND();四舍五入；ROUND(3.562,1);取一位小数TRUNCATE();数字截取；TRUNCATE(125.89,1);小数后截取一位；日期时间：NOW();当前时间；CURDATE();当前日期；CURTIME();当前时间；DATE_ADD();日期变化；DATE_ADD('2015-6-23',INTERVAL 365 DAY);DATEDIFF();俩日期之间的差值；DATE_FORMAT();进行日期格式化；SELECT DATE_FORMAT('2015-6-26','%m/%d/%Y');分类: mysql