How can I change a record to be ="current record value" + "value in another column"

AppSheet AppSheet Q&A
1

I want to update the price value in a column by adding an amount to it.

2

When do you want to do it? When adding a new record or editing an existing one?

3

Editing an existing.

4

[Update that column’s value depending on a change in another column]

1.) Turn RESET ON EDIT property of the column that you want to edit/reset to ON
2.) Click on the blue funnel and record this expression:

AND(
    IN([KeyColumn], Tablename[KeyColumn]),
    LOOKUP([_THISROW].[ChangedColumn],"Tablename","LookupColumn","ChangedColumn")<>[ChangedColumn]
)

3.) Set an Initial Value expression to this column

IF(
    NOT(IN([KeyColumn], Tablename[KeyColumn])),YourDefaultNumber,
    YourDefaultNumber+[ColumnValueToAdd]
)
5

Presumably the default number can be zero?

6

Default number can be any number including zero

7

Small problem - the lookup column could be one of three - “paid cash”, “paid card” or “paid transfer”. I was trying to do it from three different action buttons. Is that possible?

8

Its an “amount due” field and I currently have it as [Total Service]+[Total Parts]+[Shop Sale]-[Card Paid]-[Cash Paid]-[Transfer Paid] but obviously the logic doesn’t work if I then add another cost.