[Qgis-user] calculating progressive value

[Christine]

Salvatore Oliveto wrote
> Hi, I have a Qgis layer with a table with twno columns X and Y.
> The X column has a set of values​​, while in the Y column I have to enter,
> using field calculator, for each record the progressive value. Eg : X
> column values: a , b , c , d ; Y column values (to be calculated with the
> field calculator from Y column): a; a + b; a + b + c; a + b + c + d.

Hi Salvatore, 
not really sure, if I understood you properly, but you can use a "case when
... then ... else" condition in field calculator. Please adapt the following
pattern to your needs:

CASE 
WHEN X = a THEN a
WHEN X = b THEN a+b
WHEN X = c THEN a+b+c 
WHEN X = d THEN a+b+c+d
ELSE 'error value'
END

Hope this helps,
regards, Christine






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