• SQL trick: overcoming GROUP_CONCAT limitation in special cases

    July 21, 2010

    In Verifying GROUP_CONCAT limit without using variables, I have presented a test to verify if group_concat_max_len is sufficient for known limitations. I will follow the path where I assume I cannot control group_concat_max_len, not even in session scope, and show an SQL solution, dirty as it is, to overcome the GROUP_CONCAT limitation, under certain conditions. […]

  • mycheckpoint (rev. 170): improved custom queries; local charting; page/swap I/O monitoring; improved HTML reports

    July 16, 2010

    Revision 170 of mycheckpoint, a MySQL monitoring solution, has been released. New and updated in this revision: Improved custom queries: lifting of limitations from previous, introductory revision; better HTML presentation Local, inline charting: no rendering of Google Charts, unless explicitly requested. All charts are now rendered locally using JavaScript. No data is now sent over […]

  • Implicit casting you don't want to see around

    July 7, 2010

    In Beware of implicit casting, I have outlined the dangers of implicit casting. Here's a few more real-world examples I have tackled: Number-String comparisons Much like in programming languages, implicit casting is made to numbers when at least one of the arguments is a number. Thus: The second query consists of pure strings comparison. It […]

  • Tales of the Trade #4: new home for the MySQL dolphins

    July 5, 2010
  • SQL: good comments conventions

    July 1, 2010

    I happened upon a customer who left me in awe and admiration. The reason: excellent comments for their SQL code. I list four major places where SQL comments are helpful. I'll use the sakila database. It is originally scarcely commented; I'll present it now enhanced with comments, to illustrate. Table definitions The CREATE TABLE statement […]

 
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