view - mysql subtract row by row -

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i have 2 mysql (5.6) views. 1 view contains 1 value in 1 row on column. let's column , in single row have value 5000.

i have second view 3 columns: item (varchar), date (obviously containing dates) , value (decimal). second view has 4 rows looks this:

item                date             value  'lectii de pian',  '2015-11-09',     '101.88' 'microsoft office','2015-11-11',     '7.00' 'belasting',       '2015-11-15',     '524.00' 'netflix',         '2015-11-18',     '8.99'

what want create in view column let's call "b" , subtract first value in column value value in view , result subtract next value , on looks this

 item                date             value       b  'lectii de pian',  '2015-11-09',     '101.88'    '4898.12' 'microsoft office','2015-11-11',     '7.00'      '4891.12' 'belasting',       '2015-11-15',     '524.00'    '4367.12' 'netflix',         '2015-11-18',     '8.99'      '4358.13'

any ideas how achieve in mysql 5.6?

many thanks!

use @variable hold running subtraction, initializing view a.

select b.item, b.date, b.value, @running := @running - value b view2 b cross join (select @running := view1) order b.date

demo


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