Question

The MySQL manual (http://dev.mysql.com/doc/refman/5.1/en/charset-syntax.html) says:

There are default settings for character sets and collations at four levels: server, database, table, and column. The description in the following sections may appear complex, but it has been found in practice that multiple-level defaulting leads to natural and obvious results.

I’d like to interrogate a specific CHAR/VARCHAR/TEXT column and find out what encoding MySQL thinks it is. Is there an easy way to do this? I know I can use SHOW CREATE TABLE <table> to see the default charset for the table, but I’d like to do the same thing on the column level, as the docs suggest that it might not be the same as the table default.

Answer 1

You can do this in the information_schema.COLUMNS table.

SELECT 
  COLUMN_NAME,
  TABLE_NAME,
  CHARACTER_SET_NAME,
  COLUMN_TYPE,
  COLLATION_NAME
FROM information_schema.COLUMNS
WHERE TABLE_SCHEMA = 'your_database_name'

Example output from a Gallery2 database:

+-------------------------+--------------------------+--------------------+--------------+-----------------+
| COLUMN_NAME             | TABLE_NAME               | CHARACTER_SET_NAME | COLUMN_TYPE  | COLLATION_NAME  |
+-------------------------+--------------------------+--------------------+--------------+-----------------+
| g_accessListId          | g2_AccessMap             | NULL               | int(11)      | NULL            |
| g_userOrGroupId         | g2_AccessMap             | NULL               | int(11)      | NULL            |
| g_permission            | g2_AccessMap             | NULL               | int(11)      | NULL            |
| g_itemId                | g2_AccessSubscriberMap   | NULL               | int(11)      | NULL            |
| g_accessListId          | g2_AccessSubscriberMap   | NULL               | int(11)      | NULL            |
| g_id                    | g2_AlbumItem             | NULL               | int(11)      | NULL            |
| g_theme                 | g2_AlbumItem             | utf8               | varchar(32)  | utf8_general_ci |
| g_orderBy               | g2_AlbumItem             | utf8               | varchar(128) | utf8_general_ci |
| g_orderDirection        | g2_AlbumItem             | utf8               | varchar(32)  | utf8_general_ci |