查询银行柜员半小时内办理业务的记录

查询出银行柜员半小时内办理开户业务的记录。看看是否存在半个小时内办理了3笔及以上的开户业务。

给出了一张表，里面是一个柜员的操作记录，表records的结构为：

字段	数据类型
Cid（客户id）	int
Ctime（时间）	datetime

方法一：用窗口函数（需要MySQL8.0以上版本）；
方法二：常规的方法。
本案例采用了方法二。由于MySQL8.0版本安装过程曲折，未能顺利安装成功。

1、在MySQL中创建数据库bank

CREATE DATABASE bank;

2、创建表records

CREATE TABLE records(
Cid varchar(10) NOT NULL,
Ctime datetime NOT NULL
);

3、插入数据
（拟插入20条记录）

INSERT INTO records VALUES('adsf', '2017-5-27 10:55:00');
INSERT INTO records VALUES('ngfd', '2017-5-27 10:56:00');
INSERT INTO records VALUES('brsd', '2017-5-27 11:12:33');
INSERT INTO records VALUES('afdg', '2017-5-27 11:30:00');
INSERT INTO records VALUES('4045', '2017-5-27 11:33:23');
INSERT INTO records VALUES('sdsa', '2017-5-27 11:41:21');
INSERT INTO records VALUES('bvrt', '2017-5-27 11:52:55');
INSERT INTO records VALUES('4275', '2017-5-27 12:00:03');
INSERT INTO records VALUES('2578', '2017-5-27 12:04:00');
INSERT INTO records VALUES('7869', '2017-5-27 12:15:00');
INSERT INTO records VALUES('2479', '2017-5-27 12:21:20');
INSERT INTO records VALUES('4537', '2017-5-27 12:28:00');
INSERT INTO records VALUES('wefi', '2017-5-27 12:37:24');
INSERT INTO records VALUES('jrty', '2017-5-27 12:44:00');
INSERT INTO records VALUES('sdfg', '2017-5-27 12:50:11');
INSERT INTO records VALUES('sdvf', '2017-5-27 12:55:25');
INSERT INTO records VALUES('afds', '2017-5-27 13:08:00');
INSERT INTO records VALUES('jhtg', '2017-5-27 13:12:00');
INSERT INTO records VALUES('7632', '2017-5-27 13:15:00');
INSERT INTO records VALUES('fghd', '2017-5-27 13:16:00');

4、自连接
将表中每一条记录，都与20条记录连接起来，得到400条记录（即20*20）。

SELECT a.*, b.*
FROM records a, records b
ORDER BY a.Ctime, b.Ctime;

5、求时间差，新增计算字段记录该时间差

SELECT	a.Cid, 
		a.Ctime AS t1, 
		b.Cid, 
		b.Ctime AS t2,
		(b.Ctime -a.Ctime) AS t1_t2
FROM records a, records b
ORDER BY a.Ctime, b.Ctime;

6、筛选出与原20条记录相隔半个小时内的所有记录
共有41条

SELECT	a.Cid, 
		a.Ctime AS t1, 
		b.Cid, 
		b.Ctime AS t2,
		(b.Ctime -a.Ctime) AS t1_t2
FROM records a, records b
WHERE (b.Ctime -a.Ctime) > 0  AND (b.Ctime - a.Ctime) <= 3000
ORDER BY a.Ctime, b.Ctime;

7、对这41条记录，分组计数

SELECT * 
FROM (
		SELECT a.Cid, count(*) as cnt
		FROM (
				SELECT	a.Cid, 
						a.Ctime as t1, 
						b.Cid, 
						b.Ctime as t2,
						(b.Ctime -a.Ctime) AS t1_t2
				FROM records a, records b
				WHERE (b.Ctime -a.Ctime) > 0  AND (b.Ctime -a.Ctime) <= 3000
				ORDER BY a.Ctime, b.Ctime
              ) A
		GROUP BY a.Cid
      ) B
ORDER BY B.cnt DESC;

8、其它
（1）时间差。
‘2017-5-27 12:44:00’与’2017-5-27 12:50:11’，相差6分11秒，在这里计算结果显示为611。故半个小时的判断条件为：0-3000，即：WHERE ( b.Ctime -a.Ctime ) > 0 AND ( b.Ctime -a.Ctime ) <= 3000

（2）查询是否存在一个小时内办理了5笔及以上的开户业务

SELECT * 
FROM (
		SELECT a.Cid, count(*) as cnt
		FROM (
				SELECT	a.Cid, 
						a.Ctime as t1, 
						b.Cid, 
						b.Ctime as t2,
						(b.Ctime -a.Ctime) AS t1_t2
				FROM records a, records b
				WHERE (b.Ctime -a.Ctime) > 0  AND (b.Ctime -a.Ctime) <= 10000
				ORDER BY a.Ctime, b.Ctime
             ) A
		GROUP BY a.Cid
      ) B
ORDER BY B.cnt DESC;

来源：CSDN

作者：chow28

链接：https://blog.csdn.net/chow28/article/details/104459770

标签

银行柜员

银行