Can't use vlookup to count multiple occurences in same collumn?

I've been tying to get the vlookup function to not stop when it finds the 1st occurence and actually find all the occurences in that collumn and then sum them together, can this be done? Or by using a different function?

Example
ID VALUE TO BE RETURNED
blue 1
red 2
green 3
blue 4

So when vlookup looks for blue it should return 5 which is sum of 1 + 4 rather than stop when it finds 1, anyone any ideas? Thanks

wrong formula ! use sumif
=sumif(a1:a100,"blue",b1:b100)