When I run the following mysql query in Workbench it returns the desired result (see attachment).

set @csum := 0;
select condofee_date as Date, condofee_description as Description, condofee_amount as Amount, (@csum := @csum + condofee_amount) as Balance
FROM
    condominium_fees
WHERE
    apartments_apartment_id = 1
ORDER BY condofee_date;set @csum := 0;

If I run it on your plug in I get;

cannot calculate position of @csum := 0 @csum := 0 within @csum := 0; select condofee_date as Date, condofee_description as Description, condofee_amount as Amount, (@csum := @csum + condofee_amount) as Balance FROM condominium_fees WHERE apartments_apartment_id = 1 ORDER BY condofee_date;set @csum := 0;

Am I using the wrong syntax for set @csum := 0 ?

Thanks

Correct attachment here, ignore the previous one

Thanks

Thanks Aleksandar

I'm pretty sure mysql doesn't allow variables in a view either. Is there a way I can display a running balance calculated from the previous 2 columns on each row in wpdataTables?

Thanks

Mark

Thanks again

I had looked at this but couldn't see a way of creating a formula that references a cell in the previous row? Do you have an example of using the formula column to create a running total type arrangement?

Thanks again Aleksandar

I was aware of the ability to reference different columns, can I reference different rows (necessary for a running total column)?

OK, are you aware of any method of calculating a running total column calculated from either a formula column or from a query within the mysql that works within the wpdatatables environment?

OK, I moved hosting to a platform that had a more recent version of PHP (7.4) and used a 

SUM...OVER (PARTITION BY) as part of the SELECT query which has worked.