mysql随机字段[关闭]

Question

I have a mysql database with about 800 columns at the moment and add to it every so often.

How do I add a new field with a random string of 4 letters and numbers eg : 4h3k

I do not want duplicates to happen either.

Thanks chaps!

EDIT

OH MA GAD NO I MEAN ROWS NOT COLUMNS.

800 ROWS!

Answer 1

As the comments already show. Why in the world would you want 800 columns? Seems like a mayor flaw in your database structure. Perhaps you can explain what you want to store so we can help you to setup a proper structure. 800 (random!) columns can never be what you want.

If you do plan to keep this structure, you could use SHOW COLUMNS FROM mydb.mytable WHERE FIELD='newcolname' to see if it already exists.

But I highly recomment to reconsider your database model. How are you even selecting things from it since its random columns? You always use select * and then loop trough all cols?