Database Administration
Combine Query Results With UNION in MySQL
A join widens a row by adding columns; UNION instead stacks one result on top of another. Build a single contact list from a…
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Tag: Command Line
Programming
Log and Display PHP Errors
PHP decides two things separately: whether to print a problem to the browser, and whether to write it to a file. Set display_errors and…
Server Administration
Set File and Directory Permissions With chmod
Set file and directory permissions with chmod, numerically and symbolically, and you control exactly who can read, write, or execute anything on a Linux…
Database Administration
Write a Subquery in MySQL
Write a subquery in MySQL to answer a question inside a question - a SELECT nested in another statement's WHERE or column list. This…
Server Administration
Create a systemd Service
Create a systemd service to keep a long-running program alive - started at boot, restarted on a crash, logs collected. This tutorial writes a…
Server Administration
Enable Gzip Compression in Apache
Enable gzip compression in Apache with mod_deflate and every text response shrinks before it crosses the wire. This tutorial loads the module, sets AddOutputFilterByType…