Zao an! Wu an! Wan an! (Good morning / afternoon / night)

zǎo ān (Good morning!)
wǔ ān (Good afternoon!)
wǎn ān (Good night!)

Note: some people use "zao" instead of "zao an"

Explanation: 

"zao" means "early" and "an" means "good" or "peaceful"

"zao an"  means "Good morning!" 

"wu" means "afternoon"
"wu an" means "Good afternoon!"

"wan" means "late" or "night"
"wan an" means "Good night!"

Other Information:

In English, we have "Good Evening!"
In Japanese, we have "Kon Ban Wa!" (こんばんは)
In Chinese, we also have something similar~
We have "晚上好(wǎn shàng hǎo)"
However, "wǎn shàng hǎo" is seldom used...
People use other greetings (ex. Ni Hao) instead.