A lot. Commercial Driver Licenses are held to much stricter standards than the standard driver's license.
If you hold a Commercial License and are charged with DUI in a private vehicle, your privilege to operate a commercial vehicle will be suspended for one year. In the State of Alabama there are no special exceptions for suspensions.
Think about the consequences of not being able to drive for a year. Loss of income and certainly family problems.
You must act especially quickly if you have been charged with a DUI and you hold a CDL.