Jontas » MySQL

MySQL execute statements directly from the (linux) console

jontas — Wed, 18 Aug 2010 09:16:06 +0000

Executing a query quickly from the console is nice to be able to do (without having to enter the MySQL console).

This will simply output the result to the console where you are.
```
 user@server:~$ mysql -uUSERNAME -p DATABASENAME --execute "REPAIR TABLE position";
```
Replace USERNAME and DATABASENAME with your vars
If you would like the output to a file
```
 mysql -uUSERNAME -p DATABASENAME --execute "SELECT * FROM test" > test.sql;
```
Replace USERNAME and DATABASENAME with your vars
If you would like the output to be sent as a email
```
 mysql -uUSERNAME -p DATABASENAME --execute "SELECT * FROM test" | mail -s 'SUBJECT' example@mail.com
```
Replace USERNAME, DATABASENAME , SUBJECT and example@mail.com with your vars

MYSQL Creating several UUIDs at one single time

jontas — Wed, 14 Jul 2010 06:56:07 +0000

I recently ran into the problem that I had too add two rows to a database that uses a UUID (in this case converted to a binary) as a key.
The problem I had was that running two insert statements after each other (just separated by “;”) then the same id was generated.
A workaround I have found is to sleep for a second between the two statements.

Examples (using SELECT instead of INSERT):
Getting the same id twice

SELECT UNHEX(REPLACE(UUID(),'-','')) AS uuid1,  UNHEX(REPLACE(UUID(),'-','')) AS uuid2;
-- Shows: "849392548f1311df91b70019dbd264f1"	"849392908f1311df91b70019dbd264f1"

Adding a sleep to get different ids

SELECT UNHEX(REPLACE(UUID(),'-','')) AS uuid1, SLEEP(1), UNHEX(REPLACE(UUID(),'-','')) AS uuid2
-- Shows: "3901c1928f1511df91b70019dbd264f1"	"0"	"399a5b148f1511df91b70019dbd264f1"

And another one using INSERTS

INSERT INTO testTable (id) VALUES (UNHEX(REPLACE(UUID(),'-','')));
SLEEP(1);
INSERT INTO testTable (id) VALUES (UNHEX(REPLACE(UUID(),'-','')));

MySQL importing a sql file

jontas — Mon, 07 Jun 2010 08:52:27 +0000

To simply import a sql file (and get any results printed to the prompt)

mysql -uUSERNAME -p DBNAME < FILENAME

The parameters are
-u username (note no space between the u and USERNAME)
-p password (can be given as the username (without a space between p and PASSWORD; or if omitted mysql will ask for it)
DBNAME is the name of the database to import to (if the sql file don’t create a database on it’s own)
FILENAME is the name of the file to import

Other parameters can be
-h server host (dns name or ip) if -h is omitted then localhost is assumed.
-P port number
-f force (will not break on errors)

To import a sql file and then have to output to a file (for instance when running from a crontab)

mysql -uUSERNAME -p DBNAME < FILENAME > OUTFILE

Works just as the previous import except that any output will be written to OUTFILE.

mysqldump Couldn’t execute references invalid table(s) or column(s) or function(s) or definer/invoker of view lack rights to use them (1356)

jontas — Fri, 12 Feb 2010 12:27:15 +0000

If you get an error messages like “mysqldump: Couldn’t execute ‘SHOW FIELDS FROM `store_information`’: View ‘database.viewname’ references invalid table(s) or column(s) or function(s) or definer/invoker of view lack rights to use them (1356)” then a number of things might be wrong:

The view is “corrupted” (this could happen if the table the view is of has been updated in a way so that the view is no longer correct – for instance if the table structure is updated)
The user you are using are lacking permissions (to the view/table (that the view is referencing) )

What I usually do when this happens to solve it is to:

Verify if the user running the mysqldump has the permissions (or test as root if you can – as root has more permissions).
If this is the case: update the permissions on the user running the dump – or change to another user
Try to find out if the table the view is referencing has been updated (think back what have I done/check with the rest of the team)

Or if you do not wish to/can not do this, check a previous backup up the base table (from when mysqldump worked with the view) and compare the structure with the current structure in the database.

If this is the case: I just drop the view and recreate the view so that it gets corrected in the underlying db structure and re-run the dump.

More info for people using this notebook as a article; here is some manual pages that will help you along if you don’t know how to alter permissions/create views.
More information about user permissions
More information about views