It depends which planet you mean - the Earth takes 23 hours & 56 minutes to rotate once.
Neptune takes 16 hours 6 minutes and 36 seconds to rotate or spin once on its axis, or 0.67125 Earth days.
It takes 58 days for mercury to rotate on its axis.
It takes roughly 6.4 Earth days for Neptune to rotate on it's axis.
628 days.
7.5
about 63 earth days
About .997 days per full earth rotation on its own axis.
About 27.3 days.
234 years
153.3 hours
A year is the time it takes a planet to rotate about its star and a 'day' is the time it takes a planet to rotate once on its axis. Thus as the Sun is a star the concept of a 'year' is irrelevant as it is at the centre of all rotation. In relation to 'day' however, the Sun does rotate on its axis, it takes 25.38 (Earth) days to rotate once at the equator but as it is made of gas, it does not rotate all together like a solid body and the area round the poles rotates more slowly, taking 34.4 (Earth) days to make a revolution.
0.345, it takes the sun 27 days to rotate on its axis once.