问题
Is there a more-efficent, less laborious way of copying all records from one table to another that doing this:
INSERT INTO product_backup SELECT * FROM product
Typically, the product table will hold around 50,000 records. Both tables are identical in structure and have 31 columns in them. I'd like to point out this is not my database design, I have inherited a legacy system.
回答1:
There's just one thing you're missing. Especially, if you're using InnoDB, is you want to explicitly add an ORDER BY clause in your SELECT statement to ensure you're inserting rows in primary key (clustered index) order:
INSERT INTO product_backup SELECT * FROM product ORDER BY product_id
Consider removing secondary indexes on the backup table if they're not needed. This will also save some load on the server.
Finally, if you are using InnoDB, reduce the number of row locks that are required and just explicitly lock both tables:
LOCK TABLES product_backup WRITE;
LOCK TABLES product READ;
INSERT INTO product_backup SELECT * FROM product ORDER BY product_id;
UNLOCK TABLES;
The locking stuff probably won't make a huge difference, as row locking is very fast (though not as fast as table locks), but since you asked.
回答2:
mysqldump -R --add-drop-table db_name table_name > filepath/file_name.sql
This will take a dump of specified tables with a drop option to delete the exisiting table when you import it. then do,
mysql db_name < filepath/file_name.sql
回答3:
DROP the destination table:
DROP TABLE DESTINATION_TABLE;
CREATE TABLE DESTINATION_TABLE AS (SELECT * FROM SOURCE_TABLE);
回答4:
I don't think this will be worthy for a 50k table but: If you have the database dump you can reload a table from it. As you want to load a table in another one you could change the table name in the dump with a sed command: Here you have some hints: http://blog.tsheets.com/2008/tips-tricks/mysql-restoring-a-single-table-from-a-huge-mysqldump-file.html
An alternative (depending on your design) would be to use triggers on the original table inserts so that the duplicated table gets the data as well.
And a better alternative would be to create another MySQL instance and either run it in a master-slave configuration or in a daily dump master/load slave fashion.
来源：https://stackoverflow.com/questions/11188427/mysql-efficiently-copy-all-records-from-one-table-to-another