Re: CHAR vs VARCHAR

[B C]

Matthew,

The final decision is your call. Here are the pros and cons of each. The only real benefit to using CHAR is that it allows MySQL to run select statements a bit quicker since all the records are of a fixed length. I don't know how *much* quicker though. I suggest you use VARCHAR and then switch to CHAR if performance is a problem.

VARCHAR

- Trailing white space is preserved. (MySQL 5.0.3+ only.)
- Minimal storage overhead. A 17 character record takes up only 17 characters of space.
- Slower SELECTs when searching this column.

CHAR

- Trailing white space is always removed.
- Every record takes up a fixed amount of space - 19 characters in your case. Your 17 character records will waste two bytes of storage.
- Faster SELECTs when searching this column.

Source: http://dev.mysql.com/doc/refman/5.0/en/char.html