How to add current record to previous record, creating a cumulative?

I do not have much time to think of something better now, but that does.

I hope someone gives a better answer.

  SELECT 
            DAY(i.imp_data) AS DATA,
            m.mt_valor / m.mt_valor / CAST(DAY(LAST_DAY(NOW())) AS DECIMAL)* 100 AS META_DIARIA,
            SUM(i.imp_venda) / m.mt_valor * 100 AS VENDA
        FROM
            metas AS m
                LEFT JOIN
            importacao AS i ON m.mt_loja = i.imp_loja
        WHERE
            m.mt_loja = 1
        GROUP BY i.imp_data , i.imp_loja
    Union all

    Select 0 , sum(d.META_DIARIA), sum(d.VENDA)
FROM 
    (SELECT 
            DAY(i.imp_data) AS DATA,
            m.mt_valor / m.mt_valor / CAST(DAY(LAST_DAY(NOW())) AS DECIMAL)* 100 AS META_DIARIA,
            SUM(i.imp_venda) / m.mt_valor * 100 AS VENDA
        FROM
            metas AS m
                LEFT JOIN
            importacao AS i ON m.mt_loja = i.imp_loja
        WHERE
            m.mt_loja = 1
        GROUP BY i.imp_data , i.imp_loja 
    )d;

You can mount a cursor as shown below.

declare @teste table
(
  DATA int,
  META_DIARIA float,
  VENDA float
)


declare @testeAux table -- crie uma tabela auxiliar
(
  DATA int,
  META_DIARIA float,
  VENDA float
)

insert into @teste values

(1, 3.3333333333,4.289370),
(2, 3.3333333333,4.469177),
(3, 3.3333333333,6.114472),
(4, 3.3333333333,2.988198),
(5, 3.3333333333,2.903717),
(6, 3.3333333333,4.254977),
(7, 3.3333333333,2.825020),
(8, 3.3333333333,4.320407),
(9, 3.3333333333,3.985957),
(10,3.3333333333,5.961010),
(11,3.3333333333,2.829374),
(12,3.3333333333,2.855886),
(13,3.3333333333,2.859196),
(14,3.3333333333,2.812158),
(15,3.3333333333,4.580555),
(16,3.3333333333,3.297720),
(17,3.3333333333,4.736971),
(18,3.3333333333,2.325877),
(19,3.3333333333,2.488738),
(20,3.3333333333,2.059191)

declare @DATA int,  @META_DIARIA float,  @VENDA float
DECLARE product_cursor CURSOR FOR   
select DATA,  META_DIARIA,  VENDA   from @teste -- altere para seu select existente


OPEN product_cursor  
FETCH NEXT FROM product_cursor INTO @DATA,  @META_DIARIA,  @VENDA  


WHILE @@FETCH_STATUS = 0  
BEGIN  
    insert into @testeAux (DATA,  META_DIARIA,  VENDA) 
    values (@DATA,  @META_DIARIA,  @VENDA );

    insert into @testeAux ( META_DIARIA,  VENDA) 
    select sum(META_DIARIA),  sum(VENDA)  from @testeAux where DATA is not null;

    FETCH NEXT FROM product_cursor INTO @DATA,  @META_DIARIA,  @VENDA    
    END  

CLOSE product_cursor  
DEALLOCATE product_cursor  

select * from @testeAux

This example was mounted on sql server, I believe it is not difficult for you to mount it in mysql.