MySQL shell: Enable UTF-8

First do

ALTER DATABASE database_name CHARACTER SET "utf8";
ALTER DATABASE database_name COLLATE "utf8_unicode_ci";

After that, for each table:

ALTER TABLE table_name DEFAULT CHARACTER SET "utf8" COLLATE "utf8_unicode_ci";

This jus...

In a nutshell: to avoid your shell character set from messing with imports, use -r to export and SOURCE when importing.

Dumping safely

# Do not do this, since it might screw up encoding
mysqldump -uroot -p database...

Unless all MySQL server defaults are set to UTF-8, mysqldump encodes UTF-8 characters incorrectly and only outputs correct UTF-8 when you switch to Latin 1 (!). Also you need to setup charset and collation manually for each new database.

To preve...

To show the MySQL default character set you have to login to the MySQL console and execute SHOW VARIABLES LIKE 'char%';

mysql> SHOW VARIABLES LIKE  'char%';
+--------------------------+----------------------------+
| Variable_name  ...

If you get a stacktrace complaining about uninitialized constant MysqlCompat::MysqlRes a system library update might broke your gem.

You might have [switched from MySQL to MariaDB](https://makandracards.com/makandra/51171-running-rails-2-apps-w...

When using GROUP BY, MySQL now complains if the SELECT includes columns which are not part of the GROUP BY.

Reason:

There could be multiple values for those columns per group but only one value can be picked for the results.

The de...

When you have a string containing umlauts which don't behave as expected (are not matched with a regexp, can't be found with an SQL query, do not print correctly on LaTeX documents, etc), you may be encountering umlauts which are not actually umla...

This will make MySQL log all received queries so you can see for yourself what happens on the database level.

Don't switch this on for production machines!

1. Edit your my.cnf:
   sudo vim /etc/mysql/my.cnf
2. In the [mysqld] section, a...