TAKE 30 SECONDS TO READ THIS BEFORE YOU POST! State what database are you using!
I see too many questions asked in here where the answer could be different depending on what database technology (Access, Oracle, SQLServer, MySQL, PostgreSQL) is in use.
Please say what database system you are using when you ask a question!
Additionally, if youre asking about code, or including code, say what language that code is too. Mentioning what driver technology youre using to connect your database might also be needed. All in, as with any question; providing more information is better than less.