[MySQLFAQ] series-mysqldump plus-w parameter backup _ MySQL

[MySQLFAQ] series-mysqldump +-w parameter backup mysqldump

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 = nameDump 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 ('2017-06-01 ')" 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 ('2017-06-01 ') 'mydb mytable> mydump. SQL

In this case, the result condition is parsed:

WHERE id <10000 and logintime <unix_timestamp)

Upon discovery, the time condition changes:

WHERE id <10000 and logintime <unix_timestamp)

That is, it becomes:

Unix_timestamp (2007)

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