If I had to pay at the mart after shopping, would this be a transaction? Or was it just paying for multiple transactions at once? It is often unclear whether a transaction is a payment unit, a point of purchase, or an item of all the items you buy.
There is no correct answer to this. Just as you create criteria for categorization of items, you can divide them by the unit you want to understand (or search). If you break it down too finely, it's cumbersome to manage, and if it's too clunky to catch it comprehensively, you won't be able to get the details later.
Whooing recommends setting the range based on payment units. For example, when payment is made at a mart, the transaction is viewed as a transaction and entered as one transaction. However, if too much information is lumped together in this transaction, then you can enter each detailed transaction (based on cost items) and enter it. Conversely, if you had two payments and one payback for a reservation, you can add and subtract them all and treat only the final amount as a single transaction.