Using query builder to segment opt-in list is a great way to send emails to selected contacts on a specific email opt-in list. This is a great way to send emails to contacts who have donated recently or made a significant donation, but not send the email to the entire list.
To segment an opt-in list, navigate to Workflow & Automation > General > Queries and click the Create New button.
Select contacts for the filter and the selection using the drop-down and the radio button.
Select the contact record Id, name, and whatever information you wish to see in the results.
Under Filter, add either the Name or the Id of the opt-in list you wish to segment.
Use the drop-down to select the opt-in list you want to segment.
Then you will want to add additional filters to segment the list, for example segmenting contacts who have made a transaction within the last year. To do this, under Most Recent Transaction add the transaction date to the filter.
Click on the formula icon and then select Last X Days from the dropdown.
Now any contacts that are in the opt-in list that have made a transaction within the last year will appear.
Save the query and now you will be able to use this segmented list to send an email to.