How do I search for transactions with a specific account within a single register/account

@quo212  Well, it's not exactly the same thing, but there is a way to get practically what you want here.

If you create a P&L for the time period you want to consider (presumably All) and double-click on the amount for the expense you want to examine (presumably Advertising), it will open up a subreport for Advertising.

If you sort that subreport by Split, it will group the lines of the report by the Split account.

The Split account is typically the bank account used to pay the expense of the line in question.

From there, you can either ignore the Split groupings you don't need, or export it to Excel for some quick deletion.

@quo212  One additional note (that I still can't edit into my original post, Intuit

While I'm not a big fan of the Class system in QB, if you're willing to entertain its shortcomings, you could always assign a Class to the transactions associated with each bank account you use going forward; it is a new year, so this is probably about the best time to consider such a thing.

That would allow you to create a P&L by Class that should only contain transactions associated with said Class.

@quo212 

@FishingForAnswers 's advice is the easiest.  If you want a report that just shows these transaction, you can go to Reports > Accountant & Taxes > Transaction Detail by Account. Click 'Customize Report', click the 'Filter' tab, choose 'Account' under the filter list, select your checking account under account drop-down, under 'Include split detail?', select 'For detail accounts matching' and select your advertising expense account. Adjust the dates as needed.

@Rainflurry  "@FishingForAnswers 's advice is the easiest."

For once, I actually disagree with you; your answer seems a lot more efficient and accessible.

Thank you for this answer; I wasn't aware of that Filter function. Should be pretty useful in future.