(There is an updated version of this post here)
MySQL has useful extention to the GROUP BY operation: function GROUP_CONCAT:
GROUP_CONCAT(expr) – This function returns a string result with the concatenated non-NULL values from a group.
Where it can be useful?
(more…)
Suboptimal MySQL ORDER BY implementation, especially together with LIMIT is often the cause of MySQL performance problems. Here is what you need to know about MySQL ORDER BY LIMIT optimization to avoid these problems.
MySQL ORDER BY with LIMIT is the most common use of ORDER BY in interactive applications with large data sets being sorted. […]
Starting MySQL 4.1, MySQL had support for what is called derived tables, inline views or basically subselects in the from clause.
In MySQL 5.0 support for views was added.
These features are quite related to each other but how do they compare in terms of performance ?
(more…)
Today MySQL published the press release with results of Database Contest (results on German available here http://www.mysql.de/ct-dbcontest).
Peter and me spent quite some time working on this project while being employed by MySQL and it is great to see results finally publicly available.
The story began about year ago when C’T magazine had called for Database […]
Whenever I see benchmark results I try to understand if it is technical benchmark – made by people seeking the truth or it is done by Marketing department to wash your brains. Watch out. Whenever you treat marketing benchmarks as technical ones, you make make wrong decision. Take […]
Read more