delta load

Hi experts，

ADSO A -> ADSO B, the field "quant" is summation.

ADSO A has two rows of data:

DOCNUM CALDAY QUANT

123 2020-01-10 4

456 2020-01-10 -1

CALDAY is key.

The result of ADSO B is:

DOCNUM CALDAY QUANT

456 2020-01-10 3

The question is,

how to keep the DOCNUM is 123，not 456.