Grouping by transactions using custom group

grouping.sql

-- ---------------------------------------
-- Generate Data
-- ---------------------------------------
CREATE table trans_history AS
SELECT 'TRANS-A' AS transactions, '2017-08-30 08:00:00' AS history UNION ALL
SELECT 'TRANS-A' AS transactions, '2017-08-30 08:10:00' AS history UNION ALL
SELECT 'TRANS-A' AS transactions, '2017-08-30 08:20:00' AS history UNION ALL
SELECT 'TRANS-A' AS transactions, '2017-08-30 08:30:00' AS history UNION ALL
SELECT 'TRANS-A' AS transactions, '2017-08-30 08:40:00' AS history UNION ALL
SELECT 'TRANS-A' AS transactions, '2017-08-30 08:50:00' AS history UNION ALL
SELECT 'TRANS-A' AS transactions, '2017-08-30 09:00:00' AS history UNION ALL
SELECT 'TRANS-B' AS transactions, '2017-08-30 09:10:00' AS history UNION ALL
SELECT 'TRANS-B' AS transactions, '2017-08-30 09:20:00' AS history UNION ALL
SELECT 'TRANS-B' AS transactions, '2017-08-30 09:30:00' AS history UNION ALL
SELECT 'TRANS-B' AS transactions, '2017-08-30 09:40:00' AS history UNION ALL
SELECT 'TRANS-B' AS transactions, '2017-08-30 09:50:00' AS history UNION ALL
SELECT 'TRANS-A' AS transactions, '2017-08-30 10:00:00' AS history UNION ALL
SELECT 'TRANS-A' AS transactions, '2017-08-30 10:10:00' AS history UNION ALL
SELECT 'TRANS-A' AS transactions, '2017-08-30 10:20:00' AS history UNION ALL
SELECT 'TRANS-A' AS transactions, '2017-08-30 10:30:00' AS history UNION ALL
SELECT 'TRANS-A' AS transactions, '2017-08-30 10:40:00' AS history UNION ALL
SELECT 'TRANS-C' AS transactions, '2017-08-30 10:50:00' AS history UNION ALL
SELECT 'TRANS-C' AS transactions, '2017-08-30 11:00:00' AS history UNION ALL
SELECT 'TRANS-C' AS transactions, '2017-08-30 11:10:00' AS history UNION ALL
SELECT 'TRANS-C' AS transactions, '2017-08-30 11:20:00' AS history UNION ALL
SELECT 'TRANS-A' AS transactions, '2017-08-30 11:30:00' AS history UNION ALL
SELECT 'TRANS-A' AS transactions, '2017-08-30 11:40:00' AS history UNION ALL
SELECT 'TRANS-C' AS transactions, '2017-08-30 11:50:00' AS history UNION ALL
SELECT 'TRANS-C' AS transactions, '2017-08-30 12:00:00' AS history UNION ALL
SELECT 'TRANS-C' AS transactions, '2017-08-30 12:10:00' AS history UNION ALL
SELECT 'TRANS-C' AS transactions, '2017-08-30 12:20:00' AS history UNION ALL
SELECT 'TRANS-C' AS transactions, '2017-08-30 12:30:00' AS history UNION ALL
SELECT 'TRANS-B' AS transactions, '2017-08-30 12:40:00' AS history UNION ALL
SELECT 'TRANS-A' AS transactions, '2017-08-30 12:50:00' AS history UNION ALL
SELECT 'TRANS-A' AS transactions, '2017-08-30 13:00:00' AS history UNION ALL
SELECT 'TRANS-A' AS transactions, '2017-08-30 13:10:00' AS history UNION ALL
SELECT 'TRANS-A' AS transactions, '2017-08-30 13:20:00' AS history UNION ALL
SELECT 'TRANS-A' AS transactions, '2017-08-30 13:30:00' AS history UNION ALL
SELECT 'TRANS-A' AS transactions, '2017-08-30 13:40:00' AS history UNION ALL
SELECT 'TRANS-A' AS transactions, '2017-08-30 13:50:00' AS history UNION ALL
SELECT 'TRANS-A' AS transactions, '2017-08-30 14:00:00' AS history UNION ALL
SELECT 'TRANS-A' AS transactions, '2017-08-30 14:10:00' AS history UNION ALL
SELECT 'TRANS-D' AS transactions, '2017-08-30 14:20:00' AS history UNION ALL
SELECT 'TRANS-E' AS transactions, '2017-08-30 14:30:00' AS history UNION ALL
SELECT 'TRANS-E' AS transactions, '2017-08-31 14:30:00' AS history UNION ALL
SELECT 'TRANS-E' AS transactions, '2017-09-01 14:30:00' AS history UNION ALL
SELECT 'TRANS-E' AS transactions, '2017-09-02 14:30:00' AS history UNION ALL
SELECT 'TRANS-E' AS transactions, '2017-09-03 14:30:00' AS history UNION ALL
SELECT 'TRANS-E' AS transactions, '2017-09-04 14:30:00' AS history UNION ALL
SELECT 'TRANS-E' AS transactions, '2017-09-05 14:30:00' AS history UNION ALL
SELECT 'TRANS-E' AS transactions, '2017-09-06 14:30:00' AS history UNION ALL
SELECT 'TRANS-E' AS transactions, '2017-09-07 14:30:00' AS history UNION ALL
SELECT 'TRANS-E' AS transactions, '2017-09-08 14:30:00' AS history UNION ALL
SELECT 'TRANS-E' AS transactions, '2017-09-09 14:30:00' AS history UNION ALL
SELECT 'TRANS-E' AS transactions, '2017-09-10 14:30:00' AS history ;

-- ---------------------------------------
-- Query Data
-- Result: please see comment
-- ---------------------------------------
select min(transactions) transactions
, min(history) awal, max(history) akhir, count(history) jml_data
from (
	select d1.transactions, d1.history
    , @baris3 := @baris3 + case when d1.transactions = d2.transactions then 0 else 1 end grp
    from (
        select transactions, history
        , @baris1:=@baris1+1 baris
        from trans_history 
        join (select @baris1:=0) t1
        order by history
    ) d1
    left join (
        select transactions, history
        , @baris2:=@baris2+1 baris
        from trans_history 
        join (select @baris2:=1) t2
        order by history
    ) d2 
    on d1.baris = d2.baris
    join (select @baris3:=0) t3
    order by d1.history, d1.transactions
) d3
group by grp