I want to put a password into a mysql db by hashing it first, and then sending the hash. Is there a security risk here? I don't know enough about where things are happening (client vs server, etc...) to know.
Your post is light on details (because you are an idiot), so I'm going to assume your situation is like that of most beginners and you have a HTML form somewhere, a PHP script that takes the information from that form, hashes it, and passes it on to the MySQL database, and a MySQL database running on the same machine as the webserver.
What's happening when the user inputs his password and presses submit is that his password is travelling over the network in plaintext. It then arrives at the server, where the PHP script hashes it (on the server side, of course) and passes it on to MySQL (without passing over the network, so no security risk there).
What you need to do is use HTTPS, so the information is encrypted as it goes over the network. If you're dealing with a thing where users register and then log in later, you can get away with only using it for the registration step, and using something like client-side (using Javascript) hashing with a cryptographic nonce for the log-in.
If my assumption of your situation is wrong and my advice therefore unhelpful, you have only yourself to blame.