I have a motion detector that gets it power from a outlet in the carport.

I like to put a switch to cut it off.the hot wire from the sensor light running thougt the switch back through the outlet. But then I cut it off will it cut off the power to the outlet or just the sensor light ?

If you have gotten power off a receptacle, ran it to a switch, and then up to detector.
Then turning off switch will only turn off detector.

Thanks,
You could also have the wire from the motion that goes to the light, also go inside to a lamp, and you would know of activity.
You could also wire switch, so switch overrides motion. Like if you were reading in your carport, you wouldn't have to keep waving your arm to have light.
Newer ones can be switched on/off/on or combination to select override.