The rand () function in MySQL is used in the detailed

Source: Internet
Author: User
Tags mysql in rand

This article mainly introduces the rand () function in MySQL in the use of detailed, is the basic knowledge of MySQL primer, need friends can refer to the

The MySQL RAND () function call can produce a random number between 0 and 1:

?

1 2 3 4 5 6 7 Mysql> SELECT rand (), RAND (), Rand (); +------------------+-----------------+------------------+ | RAND () | RAND () | RAND () | +------------------+-----------------+------------------+ | 0.45464584925645 | 0.1824410643265 | 0.54826780459682 | +------------------+-----------------+------------------+ 1 row in Set (0.00 sec)

When an integer argument is invoked, RAND () uses the random number generator seed value. Each time a given value seed is generated, RAND () produces a repeatable series of numbers:

?

1 2 3 4 5 6 7 Mysql> SELECT rand (1), Rand (), Rand (); +------------------+------------------+------------------+ | RAND (1) | RAND () | RAND () | +------------------+------------------+------------------+ | 0.18109050223705 | 0.75023211143001 | 0.20788908117254 | +------------------+------------------+------------------+ 1 row in Set (0.00 sec)

You can use ORDER by RAND (), with the group row or value as follows:

To understand the order by RAND () function, assume that the EMPLOYEE_TBL table has the following records:

?

1 2 3 4 5 6 7 8 9 10 11 12-13 Mysql> SELECT * from EMPLOYEE_TBL; +------+------+------------+--------------------+ | ID | name | Work_date | Daily_typing_pages | +------+------+------------+--------------------+ | 1 | John | 2007-01-24 | 250 | | 2 | Ram | 2007-05-27 | 220 | | 3 | Jack | 2007-05-06 | 170 | | 3 | Jack | 2007-04-06 | 100 | | 4 | Jill | 2007-04-06 | 220 | | 5 | Zara | 2007-06-06 | 300 | | 5 | Zara | 2007-02-06 | 350 | +------+------+------------+--------------------+ 7 rows in Set (0.00 sec)

The following directories are now used:

?

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 Mysql> SELECT * from Employee_tbl ORDER by RAND (); +------+------+------------+--------------------+ | ID | name | Work_date | Daily_typing_pages | +------+------+------------+--------------------+ | 5 | Zara | 2007-06-06 | 300 | | 3 | Jack | 2007-04-06 | 100 | | 3 | Jack | 2007-05-06 | 170 | | 2 | Ram | 2007-05-27 | 220 | | 4 | Jill | 2007-04-06 | 220 | | 5 | Zara | 2007-02-06 | 350 | | 1 | John | 2007-01-24 | 250 | +------+------+------------+--------------------+ 7 rows in Set (0.01 sec)   mysql> SELECT * from Employee_tbl ORD ER by RAND (); +------+------+------------+--------------------+ | ID | name | Work_date | Daily_typing_pages | +------+------+------------+--------------------+ | 5 | Zara | 2007-02-06 | 350 | | 2 | Ram | 2007-05-27 | 220 | | 3 | Jack | 2007-04-06 | 100 | | 1 | John | 2007-01-24 | 250 | | 4 | Jill | 2007-04-06 | 220 | | 3 | Jack | 2007-05-06 | 170 | | 5 | Zara | 2007-06-06 | 300 | +------+------+------------+--------------------+ 7 rows in Set (0.00 Sec
Related Article

Contact Us

The content source of this page is from Internet, which doesn't represent Alibaba Cloud's opinion; products and services mentioned on that page don't have any relationship with Alibaba Cloud. If the content of the page makes you feel confusing, please write us an email, we will handle the problem within 5 days after receiving your email.

If you find any instances of plagiarism from the community, please send an email to: info-contact@alibabacloud.com and provide relevant evidence. A staff member will contact you within 5 working days.

A Free Trial That Lets You Build Big!

Start building with 50+ products and up to 12 months usage for Elastic Compute Service

  • Sales Support

    1 on 1 presale consultation

  • After-Sales Support

    24/7 Technical Support 6 Free Tickets per Quarter Faster Response

  • Alibaba Cloud offers highly flexible support services tailored to meet your exact needs.