Sorry,after searching the wiki,turns out I was wrong at(SGD is batch size=1).
Really sorry!
SGD is randomly chosen an example in the batch as the gradient.
Use randomly picked gradient to replace the gradient computed over all examples or batch.
So It’s reasonable to use batch size that greater than 1.
However, from my experience, It’s very unstable using SGD,which would cause your loss changes dramatically.
If you want to know more, please click here 8 and check out.
Hope I didn’t make you confused: )