In my customer database I need to filter out thousands of records based on addresses, then delete them whilst leaving the rest intact. How do I do this without reading every single record?
(Do not use a long question as the subject of a thread. Try to describe your concern in short.)
How should someone tell without knowing anything about your data and about the criteria that might be applied?
A few general statements:
A spreadsheet is not a database. Keeping data in spreadsheets often is the quick and dirty way to do something that would have better be done in a DB.
Erasing data physically is not the standard proceeding in DB concerning “deletion”. In many cases data are only marked “deleted” and then no longer taken in account for selections. Special commands can then revive “deleted” data.
If there not are conditions reliably applicable by formulae to select the records for elimination you will need to select one by one - and to accept the risk to do wrong in some cases.
If you can design a formula for the selection applicable to every record, you will dedicate a column for the selector. The selector should be a logical result of the formula then. You may also use something else easily testable. Having entered the formula into, say, S2 and filled it down as far as needed (“thousands of rows”) you can sort all your datasets using that column as the only sorting key. The sorting will be stable under any different aspect. Now you can easily select all the rows containing the “erase-selector” and erase them.
See also this demo.