CREATE TABLE tabela(
  data DATETIME,
  gw1  INTEGER,
  gw2  INTEGER,
  gw3  INTEGER
);

INSERT INTO tabela(data, gw1, gw2, gw3)
            VALUES('2019-03-19 21:03:11', -72, 0, 0),
                  ('2019-03-19 21:03:18', 0, -80, 0),
                  ('2019-03-19 21:03:26', 0, 0, -45),
                  ('2019-03-19 21:04:26', 0, 0, -50),
                  ('2019-03-19 21:04:26', 0, 0, -100),
                  ('2019-03-19 21:04:26', 0, 10, -50),
                  ('2019-03-19 21:04:26', 30, 0, -50);

SET @gw1 := 0;
SET @gw2 := 0;
SET @gw3 := 0;
SET @grupo := 1;

SELECT x.data,
       x.gw1_final AS gw1,
       x.gw2_final AS gw2,
       x.gw3_final AS gw3
  FROM (SELECT t.data,
               @gw1 := @gw1 + t.gw1 AS gw1_final,
               @gw2 := @gw2 + t.gw2 AS gw2_final,
               @gw3 := @gw3 + t.gw3 AS gw3_final,
               @mudar := CASE
                           WHEN @gw1 = 0 OR @gw2 = 0 OR @gw3 = 0 THEN 'N'
                           ELSE 'S'
                         END,
               @gw1 := CASE @mudar
                         WHEN 'S' THEN 0
                         ELSE @gw1
                       END,
               @gw2 := CASE @mudar
                         WHEN 'S' THEN 0
                         ELSE @gw2
                       END,
               @gw3 := CASE @mudar
                         WHEN 'S' THEN 0
                         ELSE @gw3
                       END
          FROM tabela t
         ORDER BY t.data
       ) x
  WHERE x.gw1_final <> 0
    AND x.gw2_final <> 0
    AND x.gw3_final <> 0;

| data                | gw1 | gw2 | gw3  |
| ------------------- | --- | --- | ---- |
| 2019-03-19 21:03:26 | -72 | -80 | -45  |
| 2019-03-19 21:04:26 | 30  | 10  | -250 |