关于MySQL onlinedb数据库的一些查询语句大全
作者:山间惊鸿宴
(1)查询users表,列出用户的所有信息。
SELECT * FROM users;
(2)查询goods表,列出商品编号、名称和进货量(库存量+销售量,列名为purchases).
SELECT gid, gname, (gquantity + gsale_qty) AS purchases FROM goods;
(3)查询users表,找出2000年以后出生的用户,列出用户名、性别和所在城市。
SELECT uname, ugender, ucity FROM users WHERE ubirthday >= '2000-01-01';
(4)查询users表,找出使用QQ邮箱的用户,列出登录名、用户名和邮箱地址。
SELECT ulogin,uname, uemail FROM users WHERE uemail LIKE '%@qq.com';
(5)查询users表,找出来自北京、广州和深圳三个城市的用户,列出用户名、性别和所在城市。
SELECT uname, ugender, ucity FROM users WHERE ucity IN ('北京', '广州', '深圳');
(6)查询单笔订单金额在5000元以上的订单号。
SELECT oid FROM orders WHERE oamount >= 5000;
(7)查询users表,列出积分排名前5的用户名和积分。
SELECT uname, ucredit FROM users ORDER BY ucredit DESC LIMIT 5;
(8)查询users表,按性别统计用户的平均年龄,列出姓名和平均年龄(avg age)。
SELECT ugender, AVG(DATEDIFF(CURDATE(),ubirthday)/365) AS `avg age` FROM users GROUP BY ugender;
(9)查询users表,统计各城市的用户人数(num),并按人数从高到低排序。
SELECT ucity, COUNT(*) AS num FROM users GROUP BY ucity ORDER BY num DESC;
(10)查询users表,列出积分排名前5的用户名、积分和名次(ranking).
SELECT uname, ucredit, ranking FROM ( SELECT uname, ucredit, RANK() OVER (ORDER BY ucredit DESC) AS ranking FROM users ) AS ranked_users WHERE ranking <= 5;
(11)查询goods表,列出所有乐器类商品的id、名称、类别id和类别名称。
SELECT gid, gname, category.cid AS category_id, category.cname AS category_name FROM goods INNER JOIN category ON goods.cid = category.cid WHERE category.cname = '乐器';
(12)查询图书类商品的总销售量(sale_count)。
SELECT SUM(gsale_qty) AS sale_count FROM goods INNER JOIN category ON goods.cid = category.cid WHERE category.cname = '图书';
(13)查询用户“郭辉”的购物车信息,列出商品id、名称、价格和数量。
SELECT cart.gid, goods.gname, goods.gprice, cart.cnum FROM cart INNER JOIN goods ON cart.gid = goods.gid INNER JOIN users ON cart.uid = users.uid WHERE users.uname = '郭辉';
(14)查询用户“郭辉”的订单信息,列出订单id、订单编号、订单金额和下单日期。
SELECT orders.oid, orders.ocode, orders.oamount, orders.ordertime FROM orders INNER JOIN users ON orders.uid = users.uid WHERE users.uname = '郭辉';
(15)查询订单号为“O210912082615101”的订单详情,列出商品名称、价格和购买量。
SELECT goods.gname, goods.gprice, ordersitem.inum FROM ordersitem INNER JOIN goods ON ordersitem.gid = goods.gid INNER JOIN orders ON ordersitem.oid = orders.oid WHERE orders.ocode = 'O210912082615101';
(16)查询购买过“平凡的世界”商品的用户信息,列出用户名、性别和出生日期
SELECT users.uname, users.ugender, users.ubirthday FROM users INNER JOIN orders ON users.uid = orders.uid INNER JOIN ordersitem ON orders.oid = ordersitem.oid INNER JOIN goods ON ordersitem.gid = goods.gid WHERE goods.gname = '平凡的世界';
(17)使用联合查询,查询来自北京、广州和深圳3个城市的用户,列出用户名、性别和所在城市。
SELECT uname, ugender, ucity FROM users WHERE ucity = '北京' UNION SELECT uname, ugender, ucity FROM users WHERE ucity = '广州' UNION SELECT uname, ugender, ucity FROM users WHERE ucity = '深圳';
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