In MySQLDump, use the-w statement for backup. mysqldump-w

Source: Internet
Author: User

In MySQLDump, use the-w statement for backup. mysqldump-w

When we use mysqldump to back up data, we have the option-where/-w. You can specify the backup conditions. The options are described as follows:

-w, --where=name  Dump only selected records. Quotes are mandatory

We can perform a test, for example:

mysqldump --single-transaction -w ' id < 10000 ' mydb mytable > mydump.sql

At this time, you can back up all records of id <10000 in mytable. Suppose we want to add a time range condition, for example:

mysqldump --single-transaction -w " id < 10000 and logintime < unix_timestamp('2014-06-01')" mydb mytable > mydump.sql

Here, you must pay attention to the single quotation marks and double quotation marks to avoid this situation:

mysqldump --single-transaction -w ' id < 10000 and logintime < unix_timestamp('2014-06-01') ' mydb mytable > mydump.sql

In this case, the result condition is parsed:

WHERE id < 10000 and logintime < unix_timestamp(2014-06-01)

Upon discovery, the time condition changes:

WHERE id < 10000 and logintime < unix_timestamp(2014-06-01)

That is, it becomes:

unix_timestamp(2007) -- 2014-6-1 = 2007

This is very different from our original vision, so we must be cautious.

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.