To expand on this topic a little more, you can also query against a
specific block or list of blocks.
The
Blocked Patrons Report
can always get you a list of the patrons with a specific block or list of blocks, but if you want the results as a query set, or want to include this as criteria in a larger query, you can also query by the block numbers. You can find the list of block numbers for reference either on the Blocked Patrons Report screen or in Administration - Blocks Maintenance.
For example, to Query for all patrons blocked because they are missing a birth date, add this line to your Active patrons query:
- Blocks | Block Number | In | 532,534
Or for just the patrons blocked because they are under 18 and do not have a Parent/Guardian Alt Contact:
- Blocks | Block Number | Equals | 535
This works for your local blocks as well as the system owned ones. So if you have a block for "Verify Address - Mail Being Returned" with a Block Number of 1,002 (for example--the number may be different in your system!), you could
subtract just those patrons from your query for a bulk mailing by querying for the following, and using Merge Queries (In A not

to remove them from your original query:
- Blocks | Block Number | Equals | 1002