Pick up a stick above, similar to the following data, id for the few lines in addition to the field C, 3 other field values are the same, how to find out a data only, I tried some distinct useless, because the duplicate data content is not the same,
A B C

 Id 
Qing bamboo 0707 1 
2 color scale 0410 2 
3 Lin 0102 1 
3 0102 Lin 2 
3 Lin 0102 3 

Not to repeat, only check id to search on the net A lot of similar select distinct id, A, B, Max (C) from A
Group by id, A, B such answer, but doesn't seem to apply this, and type C is varchar database field, also use the Max.. O bosses action