How do retrieve unique rows where all all columns are the same except id
Omit the ID column from your SELECT ... statement and and a DISTINCT. As in: 

SELECT DISTINCT COLUMN2, COLUMN3, .... FROM TABLE1


If you want to find how many rows exist for the same values then do a COUNT() combined with a GROUP BY. As in:

SELECT COUNT(ID), COLUMN2, COLUMN3, COLUMN4, .... 
    FROM TABLE1 
    GROUP BY COLUMN2, COLUMN3, COLUMN4, ....


Reference Material (MySQL Dev Site)


8.2.1.18 DISTINCT Optimization
3.3.4.8 Counting Rows  
12.20.2 GROUP BY Modifiers