Changing character set in MySQL

Question

When I started my website I set all the table columns to "utf8_general_ci" thinking this would make everything store in UTF8.

According to the mysql_client_encoding() function in PHP, I've been using the latin1 for my connection all along.

I understand this isn't a new problem. My question is how do I correctly update my database so that it utf8 and without affecting the data that exists in my tables?

There are a bunch of answers StackOverflow but a lot I find vague. A couple more helpful ones were:

Query all data and update as UTF8 https://stackoverflow.com/a/2335254/158126

Use a script built to convert tables https://stackoverflow.com/a/13400547/158126

In your experience, what have you done to fix this issue and retain all user data in the MySQL tables?

Answer 1

For your situation, I'd suggest trying to following for each bad column (connected over a utf8 connection):

// create a new column to store the latin1
alter table <table> add <column-latin1> <length> character set latin1;

// copy the utf8 data into the latin1 column without charset conversion
update <table> set <column-latin1> = binary <column-utf8>;

// verify the latin1 data looks OK
select <column-latin1> from <table>;

// copy the latin1 column into the utf8 column WITH charset conversion
update <table> set <column-utf8> = <column-latin1>;

// verify the new, properly encoded UTF8 data looks OK
select <column-latin1> from <table>;

// remove the temporary columns
alter <table> drop <column-latin1>;

And set your clients to use a UTF8 connection.