Minimum tenure of residence required to get family visa?(update latst

Dear All,
Can anyone please tell me the current rules and regulations for the family joining visa (spouse and 2 kids)?
It will be more helpful if you can elaborate the formalities for this here.
I am residing in UAE with family and my company is now shifting me to their new office in Muscat next month.
The only one typical issues is not clear to me :
***** Bank Statements or residence period of - 3 or 6 months required?*****for me to get my family there. This is a major query because my Kid is studying here and in between he has to drop studies for these period which is not acceptable at all to any parents.
Rest all paper work can be cleared and can get easily anyway.

Regards,
Manauar