Question: I can't seem to use mysqldump to dump a table that has been created as a MyISAM merge table.

When I attempt to, it simply dumps a file that has the create table syntax in it (correct) but not any of the data within the underlying tables.

Is this expected or a known bug? How can I replicate the behavior of mysqldump on a MRG\_MyISAM table?

Answer: 
That should be expected. The MERGE table is just a mapping of MyISAM tables.

You must dump the underlying tables.

If you want some kind of emulation to mysqldump a MERGE table (for a Table called mydb.mymergetable whose storage engine is Mrg\_MyISAM)

```
USE mydb
CREATE TABLE myhardtable LIKE mymergetable;
ALTER TABLE myhardtable ENGINE=MyISAM;
INSERT INTO myhardtable SELECT * FROM mymergetable;

```

Now, just do this:

```
mysqldump -u... -p... mydb myhardtable > /root/MyMergeData.sql

```

You could also do this

```
SELECT * INTO OUTFILE '/root/MyMergeData.sql'
FIELDS TERMINATED BY ',' OPTIONALLY ENCLOSED BY '"'
FROM mydb.myhardtable;

```
MySQL lists a number of common problems with MyISAM merge tables. Without more code I can't identify your specific problem, but this is a good place to start: <http://dev.mysql.com/doc/refman/5.1/en/merge-table-problems.html>