如何从MySQL的20个最新行中选择5个随机行？

2024-05-18 22:28:03 106

对于随机，请使用RAND()方法。对于行的限制，请使用LIMIT()方法。

让我们首先创建一个表-

create table DemoTable
   -> (
   -> ShippingDate datetime
   -> );

使用插入命令在表中插入一些记录-

insert into DemoTable values('2019-01-01');

insert into DemoTable values('2019-01-03');

insert into DemoTable values('2019-01-05');

insert into DemoTable values('2019-01-07');

insert into DemoTable values('2019-02-02');

insert into DemoTable values('2019-02-04');

insert into DemoTable values('2019-02-12');

insert into DemoTable values('2019-02-24');

insert into DemoTable values('2019-02-25');

insert into DemoTable values('2019-03-10');

insert into DemoTable values('2019-03-11');

insert into DemoTable values('2019-03-12');

insert into DemoTable values('2019-03-14');

insert into DemoTable values('2019-03-16');

insert into DemoTable values('2019-03-18');

insert into DemoTable values('2019-03-20');

insert into DemoTable values('2019-03-25');

insert into DemoTable values('2019-03-28');

insert into DemoTable values('2019-03-29');

insert into DemoTable values('2019-04-03');

insert into DemoTable values('2019-04-03');

insert into DemoTable values('2019-04-04');

insert into DemoTable values('2019-04-06');

insert into DemoTable values('2019-04-09');

insert into DemoTable values('2019-05-01');

insert into DemoTable values('2019-05-13');

insert into DemoTable values('2019-05-15');

insert into DemoTable values('2019-05-16');

insert into DemoTable values('2019-05-18');

使用select语句显示表中的所有记录-

select *from DemoTable;

输出结果

这将产生以下输出-

+---------------------+
| ShippingDate        |
+---------------------+
| 2019-01-01 00:00:00 |
| 2019-01-03 00:00:00 |
| 2019-01-05 00:00:00 |
| 2019-01-07 00:00:00 |
| 2019-02-02 00:00:00 |
| 2019-02-04 00:00:00 |
| 2019-02-12 00:00:00 |
| 2019-02-24 00:00:00 |
| 2019-02-25 00:00:00 |
| 2019-03-10 00:00:00 |
| 2019-03-11 00:00:00 |
| 2019-03-12 00:00:00 |
| 2019-03-14 00:00:00 |
| 2019-03-16 00:00:00 |
| 2019-03-18 00:00:00 |
| 2019-03-20 00:00:00 |
| 2019-03-25 00:00:00 |
| 2019-03-28 00:00:00 |
| 2019-03-29 00:00:00 |
| 2019-04-03 00:00:00 |
| 2019-04-03 00:00:00 |
| 2019-04-04 00:00:00 |
| 2019-04-06 00:00:00 |
| 2019-04-09 00:00:00 |
| 2019-05-01 00:00:00 |
| 2019-05-13 00:00:00 |
| 2019-05-15 00:00:00 |
| 2019-05-16 00:00:00 |
| 2019-05-18 00:00:00 |
+---------------------+
29 rows in set (0.00 sec)

以下是从20个最新行中选择5个随机行的查询-

select tbl1.* from (select *from DemoTable ORDER BY ShippingDate DESC LIMIT 20 ) as tbl1
   -> ORDER BY RAND() LIMIT 5;

输出结果

这将产生以下输出-

+---------------------+
| ShippingDate        |
+---------------------+
| 2019-03-14 00:00:00 |
| 2019-05-13 00:00:00 |
| 2019-03-25 00:00:00 |
| 2019-05-16 00:00:00 |
| 2019-03-10 00:00:00 |
+---------------------+
5 rows in set (0.04 sec)

如何从MySQL的20个最新行中选择5个随机行？

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