Are you tired of manually generating test data for your MySQL tables? If you’re looking for random data generator, look no further! Introducing the MySQL Random Data Generator, a powerful…

The post How To Generate Random test Data In MySQL first appeared on Change Is Inevitable.

Originally way to handle warnings and errors in MySQL stored routine was designed as follows:

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• if warning was generated during stored routine execution which has a handler for such a warning/error, MySQL remembered the handler, ignored the warning and continued execution
  
• after routine is executed MySQL checked if there is a remembered handler and activated if any
  
  

This logic was not ideal and causes several problems, particularly:

• 
  
• it was not possible to choose right handler for an instruction which generated several warnings or errors, because only first one was chosen
  
• handling conditions in current scope messed with conditions in different
  
• there were no generated warning/errors in Diagnostic Area that is against SQL Standard.
  
  
…

I’ve been updating my (sadly very very neglected, and hacked) blog recently, and along with the new look and feel, have put together a new page for ps_helper (a schema of helper views and procedures for analyzing MySQL’s Performance Schema data):

http://www.markleith.co.uk/ps_helper/

I’ve also updated it with the things that I’ve talked about recently (including my last post on Statement Digests), and put together a couple of version specific scripts, that can be used against 5.5 or the new 5.6 versions.

Each view or procedure now has examples, and their source individually listed too, so that you can see the benefits that you may get from …

MySQL 5.6.5 was released recently, with many a great blog written by various developers involved in making it such an awesome …

MySQL Connect is taking place on September 29 and 30 in San Francisco. The early bird discount enabling you to save US$ 500 is only running for a few more days, until July 13.

Are you still wondering if you should sign up? Here are 10 reasons why you definitely should:

• Learn from other companies how they tackled similar challenges to the ones you’re facing. Find out what they learned along the way, and how you can save time, money and a lot of troubles by avoiding repeating the same mistakes and applying the best practices they’ve developed. You’ll get the chance to hear from organizations including PayPal, Verizon, Twitter, Facebook, Ticketmaster, Ning, Mozilla, CERN, Yahoo! …

I recently released a new version of the Bazaar plugin for Jenkins. This release was inspired by a problem we noticed at Percona. It is:

• run “bzr revert” after a pull, as if you have a directory that is removed and re-added while having unknown files in said directory (e.g. build artifacts), you would end up in a very bad place (this is a BZR bug, so we work-around it with a “bzr revert”).

The update has already appeared in the Jenkins update centre, so you should already be able to upgrade to it.

Prepared statements have been with MySQL since version 4.1, including the protocol plumbing that helps support it.  What I didn’t realize – until a recent expedition through a general query log – is that the mysql command-line interface doesn’t implement the protocol commands that support this explicitly.  I came to this realization after observing a byproduct of this behavior.

The initial observation that triggered this exploration was noting that PREPARE and EXECUTE statements, when issued from the mysql command-line interface, result in two entries per command in the general query log:

6 Query    PREPARE stmt FROM 'SELECT RAND()'
6 Prepare    SELECT RAND()
6 Query    EXECUTE stmt
6 Execute    SELECT RAND()

Contrast this behavior with what is seen when a client sends COM_PREPARE and COM_EXECUTE, such as below with Connector/J (and useServerPrepStmts=true):

14 Prepare    SELECT * FROM t1 WHERE …

I was stunned when a SQL query raised an ERROR 1630 (42000) telling me the SUM function didn’t exist in MySQL 5.5.23. The fix was simple. The opening parenthesis of the SUM function must be on the same line as the SUM keyword without an intervening white space. Alternatively phrased, you can’t have a line return or white space between the SUM function name and the opening parenthesis of the call parameter list. The same rule doesn’t apply to the opening parenthesis of the FORMAT function and it seems to me that this parsing inconsistency is problematic.

Therefore, my surprise, observation, and complaint is that all functions don’t parse the same way, using the same rules. That is, unless you use specialized SQL_MODE settings. This assumption was borne out by Kolbe Kegel’s comment on this post, and there are 30 …

While we at mysqljoin.com want to provide simply and straightforward tutorials which are easy to understand, we love in depth documentation as well. And since relational databases are very complex, a documentation can be much more technical than our tutorials are.

We just came across such a documentation, a very detailed explanation of SQL join types. We felt that we have to share this with our readers. It’s a very nice follow up reading for everybody who’s currently learning about MySQL joins. Beside many interesting facts you’ll find probably the most interesting visualisation of joined tables we’ve ever seen as well as a visualized classification schemes for SQL joins.

There are different classification schemes and different criteria according to what joins are classified. As a result there is a bit mess in the process of understanding them. …

I thought it would be useful if people could simply ask questions about MySQL joins and have a place where they get an answer. Do you think it’s a useful feature?

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