Execuation Order¶
A SQL statement selects rows and columns from a big (rectangular) table.
You put columns that you want to select after SELECT
and rows you want to select after FROM.
A SQL statement is executed as follows.
First,
the (INNER|LEFT|RIGHT|FULL) JOIN (ON) is executed if any (see more explanation later).
Second,
the WHERE
Map Keys in macOS
Update: As of MacOS Sierra 10.12.1,
the remapping of Caps Lock to Escape can be done natively in the Keyboard System Preferences pane.
Follow the steps below to remap Caps Lock to Escape (without relying on 3rd party software).
- Open System Preferences and click on
Keyboard - Click on …
Map Keys in Windows
** Things on this page are fragmentary and immature notes/thoughts of the author. Please read with your own judgement! **
If you are a heavy Vim user and you have work on Windows, it is suggested that you Swap the Caps Lock key with the Escape key. The swaped key mapping …
Convert Format of Videos Using Using Python
Convert a Video to MP4 Using python-opencv¶
The code below converts a MOV vidoe file to a MP4 vidoe file using OpenCV in Python.
Extract Images from Video Using OpenCV in Python
Tips and Traps¶
- Most videoes have a FPS of 24. Some videos have higher FPS (e.g., 30 or 60) so that they can capture motions better. A record video on a computer has a FPS of the refresh rate of the monitor, which is usually 60. You can get the FPS of a video using OpenCV in Python.