When we use mysqldump to back up data, we have a where-w option, which can be used to specify the backup conditions. This option is interpreted as:-w, -- wherenameDumponlyselectedrecords. quotesaremandatory we can do a test, for example: mysqldump -- single-transaction-wid10000mydbmytable
When we use mysqldump to back up data, there is an option where/-w, you can specify the backup conditions, this option is interpreted as:-w, -- where = name Dump only selected records. quotes are mandatory we can do a test, for example: mysqldump -- single-transaction-w 'id 10000 'mydb mytable
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 ('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) -- 2014-6-1 = 2007
This is very different from our original vision, so we must be cautious.