How to do a value check in the form?

I have a form with dropdown list, based on google sheet table, and value i want to check.

Table has column ‘Name’ and ‘Remainder’.

How to check that input value <= remainder in table?

In the Valid If constraint try this:

[_THIS] <= [Remainder]

Table looks like

‘Name’ ‘Reminder’

aaa 120

bbb 150

ccc 200

How I can find reminder by name from dropdown list and compare it with input value?

You cannot use Table[ColumnName] in a numerical comparison, because it returns a list of values. Your question only indicated that you needed a comparison that the current column value needed to be less than or equal to another column value. If you want a list of suggested values instead then use the suggested values setting. If the dropdown ‘Name’ is by chance a REF column then the valid if would become [_THIS] <= [Ref Column].[Remainder]

Sorry, I`m new in AppSheet and not understand.

I have a table like above with columns ‘Name’ and ‘Available’ and create dropdown list from ‘Name’.

Now how can I find “Available” for the selected name and compare it to the “Input” value?

Thanks.