Hi Naomi,

> Or what is the exact deal with FOR and BINARY index?

BINARY indexes only work for expressions that can be either true or false (not null, not anything else). They are - some potential format conversions aside - exact copies of the Rushmore bitmap created in memory. That is, they consist of one large block where the first bit corresponds to the value for the first record, the second bit the value for the second record, and so on. The position of a bit defines the record number to which it applies. Contrary to all other index types the record number is not stored as part of the index. Therefore it's crucial that the index must include all records. That means filtering isn't possible.