Question

Get data week-wise my mysql since jan-2011. Timestamp is unix time stamp.so that i can see number of entries made per week since jan-2011 and analyse it

Answer 1

As Eljakim suggested: use some function to get the week and then aggregate the data using GROUP function to get it by week

SELECT year(from_unixtime( ... )), week(from_unixtime( ...) ), COUNT(*) 
GROUP BY year(from_unixtime( ... )), week(from_unixtime( ...) );

Add some WHERE clause to get only data as of 2011.