SET NAMES utf8 in MySQL?

Question

I often see something similar to this below in PHP scripts using MySQL

query("SET NAMES utf8");   

I have never had to do this for any project yet so I have a couple basic questions about it.

1. Is this something that is done with PDO only?
2. If it is not a PDO specific thing, then what is the purpose of doing it? I realize it is setting the encoding for mysql but I mean, I have never had to use it so why would I want to use it?

Answer 1

It is needed whenever you want to send data to the server having characters that cannot be represented in pure ASCII, like 'ñ' or 'ö'.

That if the MySQL instance is not configured to expect UTF-8 encoding by default from client connections (many are, depending on your location and platform.)

Read http://www.joelonsoftware.com/articles/Unicode.html in case you aren't aware how Unicode works.

Read http://stackoverflow.com/questions/1650591/whether-to-use-set-names to see SET NAMES alternatives and what exactly is it about.

Answer 2

From the manual:

SET NAMES indicates what character set the client will use to send SQL statements to the server.

More elaborately, (and once again, gratuitously lifted from the manual):

SET NAMES indicates what character set the client will use to send SQL statements to the server. Thus, SET NAMES 'cp1251' tells the server, “future incoming messages from this client are in character set cp1251.” It also specifies the character set that the server should use for sending results back to the client. (For example, it indicates what character set to use for column values if you use a SELECT statement.)