joepie91

Don't use VPN services.

No, seriously, don't. You're probably reading this because you've asked what VPN service to use, and this is the answer.

Note: The content in this post does not apply to using VPN for their intended purpose; that is, as a virtual private (internal) network. It only applies to using it as a glorified proxy, which is what every third-party "VPN provider" does.

• A Russian translation of this article can be found here, contributed by Timur Demin.
• A Turkish translation can be found here, contributed by agyild.
• There's also this article about VPN services, which is honestly better written (and has more cat pictures!) than my article.

Kartones

PSQL

Magic words:

psql -U postgres

Some interesting flags (to see all, use -h or --help depending on your psql version):

• -E: will describe the underlaying queries of the \ commands (cool for learning!)
• -l: psql will list all databases and then exit (useful if the user you connect with doesn't has a default database, like at AWS RDS)

mheadd

#!/bin/bash
UP=$(pgrep mysql | wc -l);
if [ "$UP" -ne 1 ];
then
        echo "MySQL is down.";
        sudo service mysql start

else
        echo "All is well.";
fi

tadas-s

#!/bin/bash

# Disclaimer - make backups, use at your own risk.
#
# Based on this comment: http://stackoverflow.com/a/13944924/843067
# Views and stored procedures have to be done separately.

OLDDB="old_db_name"
NEWDB="new_db_name"
MYSQL="mysql -u root -pyour_password "

bryhal

DROP TABLE IF EXISTS time_dimension;
CREATE TABLE time_dimension (
        id                      INTEGER PRIMARY KEY,  -- year*10000+month*100+day
        db_date                 DATE NOT NULL,
        year                    INTEGER NOT NULL,
        month                   INTEGER NOT NULL, -- 1 to 12
        day                     INTEGER NOT NULL, -- 1 to 31
        quarter                 INTEGER NOT NULL, -- 1 to 4
        week                    INTEGER NOT NULL, -- 1 to 52/53
        day_name                VARCHAR(9) NOT NULL, -- 'Monday', 'Tuesday'...

Usse

CREATE FUNCTION `lat_lng_distance` (lat1 FLOAT, lng1 FLOAT, lat2 FLOAT, lng2 FLOAT)
    RETURNS FLOAT
    DETERMINISTIC
    BEGIN
        RETURN 6371 * 2 * ASIN(SQRT(
            POWER(SIN((lat1 - abs(lat2)) * pi()/180 / 2),
            2) + COS(lat1 * pi()/180 ) * COS(abs(lat2) *
            pi()/180) * POWER(SIN((lng1 - lng2) *
            pi()/180 / 2), 2) ));
    END