SHOW databases; -- 查看数据仓库
USE shop;-- 使用仓库
SHOW TABLES;-- 查看表
-- 创建
CREATE TABLE proudct(id INT NOT Null PRIMARY KEY auto_increment);
DESC proudct; -- 查看表结构
ALTER TABLE proudct add COLUMN name VARCHAR(20);
ALTER TABLE proudct add COLUMN price int;
ALTER TABLE proudct add COLUMN type VARCHAR(20);
INSERT INTO proudct VALUES (1,'外套A',300,'衣服');
SELECT * FROM proudct;-- 查询表中的所有列和所有记录
INSERT INTO proudct VALUES (2,'外套B',350,'衣服');
INSERT INTO proudct VALUES (3,'鞋子A',100,'鞋');
SELECT * FROM proudct WHERE type='衣服';-- 加条件查询(where)
SELECT * FROM proudct WHERE type='鞋';-- 加条件
SELECT name,price FROM proudct;-- 查询指定字段
SELECT type from proudct;-- 查询有几种类型
SELECT type from proudct GROUP BY type; -- 分组
SELECT DISTINCT type from proudct;-- 去重关键字DISTINCT
SELECT type,COUNT(*) FROM proudct GROUP BY type; -- count统计
-- 所有商品名和商品价格
SELECT name,price from product;
SELECT name,price,price * 0.8 AS price2 FROM Proudct;
-- 打八折
SELECT name AS product_name,price,price * 0.8 AS price2 FROM Proudct;
-- 价格超过三百额的打八折
SELECT name,price,price * 0.9 AS price2 from Proudct where price <=300;
SELECT name,price,price * 0.9 AS price2 from Proudct where price <=300 AND type='衣服';
INSERT INTO proudct VALUES (4,'外套D',800,'衣服');
INSERT INTO proudct VALUES (5,'外套E',10000,'衣服');
INSERT INTO proudct VALUES (6,'外套C',300,'衣服');
-- insert into proudct (name,price,type) VALUES ()
SELECT * FROM proudct;
-- 总计
SELECT sum(price) from proudct;
-- 整个商品的平均售价
SELECT AVG(price) from proudct;
-- 最贵的售价
SELECT MAX(price),MIN(price) from product;
mysql 的基础语句
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