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Displaying posts with tag: window (reset)
How to Reduce Syntactic Overhead Using the SQL WINDOW Clause

SQL is a verbose language, and one of the most verbose features are window functions.

In a stack overflow question that I’ve encountered recently, someone asked to calculate the difference between the first and the last value in a time series for any given day:


volume  tstamp
29011   2012-12-28 09:00:00
28701   2012-12-28 10:00:00
28830   2012-12-28 11:00:00
28353   2012-12-28 12:00:00
28642   2012-12-28 13:00:00
28583   2012-12-28 14:00:00
28800   2012-12-29 09:00:00
28751   2012-12-29 10:00:00
28670   2012-12-29 11:00:00
28621   2012-12-29 12:00:00
28599   2012-12-29 13:00:00
28278   2012-12-29 14:00:00

Desired output

first  last   difference  date …
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MySQL Configuration Wizard - Don't always trust it...

So, the MySQL Configuration Wizard for making MySQL Easier to use on Windows will just plainly aid in setting up a safe and sound MySQL Configuration. Right? Just run it and you are safe. OK? But thing do break, specifically harddrives and stuff, so to keep your database in shape you have a second set of disks in your Windows machine, for all that data that you do not want to loose in RAID configuration. Or you might even connect, say, your D:-drive to an expensive but safe SAN! Then you run the MySQL Configuration Wizard and tell it to place your InnoDB data files in that D: drive. Phew! Now you are OK! That RAID-set was expensive, but better safe than sorry! Now you can place all that important data into MySQL, and what's left on the C:-drive is just some programs, which can be replaced if necessary, but the data is safe!

NO! That's NOT how it works, not at all. There are two things wrong here:

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