Làm thế nào để có được Số dư chạy mới từ Số dư hiện có?

Một Case statement có thể xử lý tình trạng của bạn.

SELECT id ID, token TK, actual_pay PAY,
       IF(@rtp IS NULL, @rtp:=token, @rtp:[email protected]+actual_pay) RTP,
       IF(@bal IS NULL, @bal:=actual_pay-token, @bal:[email protected]) BAL,

       (case IF(@rtp IS NULL, @rtp:=token, @rtp:[email protected]+actual_pay)
         when IF(@rtp IS NULL, @rtp:=token, @rtp:[email protected]+actual_pay) <= 
              (select token from token_table where id = a.id+1)
         then 1
        else 0
       end case) stat,

      (case IF(@bal IS NULL, @bal:=actual_pay-token, @bal:[email protected])
        when IF(@bal IS NULL, @bal:=actual_pay-token, @bal:[email protected]) <= 
             (select token from token_table where id = a.id+1)
        then 0
       else 
        IF(@bal IS NULL, @bal:=actual_pay-token, @bal:[email protected]) - 
        (select token from token_table where id = a.id+1)
      end case) nbal,

      (case IF(@bal IS NULL, @bal:=actual_pay-token, @bal:[email protected])
        when IF(@bal IS NULL, @bal:=actual_pay-token, @bal:[email protected]) <= 
             (select token from token_table where id = a.id+1)           
        then
            (select token from token_table where id = a.id+1)  -
            IF(@bal IS NULL, @bal:=actual_pay-token, @bal:[email protected])
       else 
        IF(@bal IS NULL, @bal:=actual_pay-token, @bal:[email protected]) - 
        (select token from token_table where id = a.id+1)
      end case) ntk

FROM token_table a
JOIN (SELECT @rtp:=NULL, @bal:=NULL) b;