This quiz is based on an email I got from a somewhat annoyed Jesper Krogh.

btw, I’m still looking for new entries. I get quite a few suggestions, but not all of them make it into quiz questions. Do send in your suggestions!

Given:

SELECT * FROM car_parts:
+---------+---------+-------+--------+
| part_id |  car_id | price | weight |
+---------+---------+-------+--------+
|       1 |       1 |  2.20 |   3.00 |
|       2 |       1 |  3.30 |   5.00 |
|       3 |       1 |  4.40 |   7.00 |
|       4 |       2 |  2.20 |   9.00 |
|       5 |       2 |  3.30 |  11.00 |
|       6 |       2 |  4.40 |  13.00 |
+---------+---------+-------+--------+

We want to know the least expensive part of each car, and how much that part weighs:

SELECT car_id, MIN(price), weight
FROM parts
GROUP BY car_id;
+---------+------------+--------+
|  car_id | MIN(price) | weight | …

For starters, it's the first tutorial I get to host at the Users Conference, and this is understandably satisfactory in itself.
Then, because it is going to give me the technical room that I was longing for. I have been writing and speaking about MySQL Proxy for 10 months, and on every occasion I felt that I had time or space limitations. There was not enough time to explain all that we …

You have to love error messages some times. Today in MySQL is was “ERROR 1289 (HY000): The ‘UNKNOWN’ feature is disabled;”

What was even more interesting is the error message and indeed the error number changed across different versions. I took the time to also review the error in the current versions of 5.0, 5.1 and 6.0.

5.0.37/5.0.51a - ERROR 1289 (HY000): The ‘InnoDB’ feature is disabled; you need MySQL built with ‘InnoDB’ to have it working
5.1.19/5.1.23/6.0.4 - ERROR 1286 (42000): Unknown table engine ‘InnoDB’
6.0.0 - ERROR 1289 (HY000): The ‘UNKNOWN’ feature is disabled; you need MySQL built with ‘UNKNOWN’ to have it working

You can read more at Bug #29373

I wrote a User-Defined Function that implements the FNV (Fowler-Voll-No) hash function for MySQL. I’m not the first person to do this — in fact, I was inspired by the Google patches for MySQL. But my implementation is a little bit different from most, in a very important way that leads directly to much higher performance, especially suited for the Maatkit tools.

A bit of background: FNV hashing is a very fast hash algorithm that operates in fixed memory. It is widely used in lots of important areas in computer science. My implementation requires absolutely no malloc() calls, which is a darn good thing because I am not to be trusted with malloc(), having spent too …

We had the Meetup in Austin featuring Zack Urlocker on March 9th. He was in Austin for the South By Southwest Festival. Part of SWSX was Sun's sponsored concert by Seven Mary Three and the Smithereens. Plus there was the added bonus of meeting members of the local community and SWSX conference attendees. And it was a good opportunity for the Texas MySQL-ers to gather together. Long story short is that we had a great meal, met some very nice people from Sun, and head lots of great music. Look for the Sun/MySQL Meetup/Mashup near you. The people are great and the events are a lot of fun!

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I was asked which is a better certification for the 'average' PHP developer : The Developer or DBA? Most of the PHP shops I know of (or have employed me) are very small and one person has to cover a lot of territory. This brings us to a 'which came first, the …

Sometimes I see people having great difficulties in describing how to fetch data for a report.They are unable to reason by sets and tend to describe things in procedural terms.Here I'm posting a small example of how you can write a query that reproduces that procedural reasoning and lets the optimizer do the work of translating it into efficient SQL.Say someone has a table structure like this, a

Open Source means that the source code is open. There are many inferences that can be made from this, and many stereotypes that can be applied, but in the end, all it means is that you can read the source code as well as use the binaries. I am not a developer. I fully [...]

I attended the Sun Tech Days last week here in Sydney, Australia with a number of objectives in mind. The first was to meet up with people I knew in Sun to see how the newly confirmed merger was working here in Australia and also to see some of the talks scheduled, particularly the database related ones.

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I attended the Sun Tech Days last week here in Sydney, Australia with a number of objectives in mind. The first was to meet up with people I knew in Sun to see how the newly confirmed merger was working here in Australia and also to see some of the talks scheduled, particularly the database related ones.

read more

The March (pun!) continues. Bill Boebel, CTO of Mailtrust (Rackspace’s mail division), saw my previous announcement and asked me to present CouchDB as part of their Racklabs series and I happily agreed. This is a very cool opportunity to meet a bunch of very smart engineers; I am eager to go.

On Monday 17th (St. Patrick’s Day) at 6pm Eastern Time, we meet at Mailtrust’s office. See the announcement for directions and details. There will be pizza and beer afterwards. The talk is open …