OnLine Optimizer with compound indices??

I have a table with a compound index on two fields (we have many examples such as this, often with more fields, but let's use this example for the sake of discussion). For example, I have fields a & b. Now, I want to do a select such as: select a,b from my_table where a || b > "XXXX" (The value "XXXX" spans both column a and b). This causes the optimizer to apply a filter as it reads *ALL* index values (at least that seems to be the case, based on the long "think" time before the first record is returned). However, if I were to just say '... where a > "XX"', or something similar, Informix would quickly jump to the correct value. Since the index is on (a,b), I don't see why my example can't work the same way. If you've had any experience with similar queries (using concatenated values), I'd appreciate any input you might have. Thanks... -- ------------------------------------------------------------------------------- Todd Saylor | Bi-Tech Software, Inc. "No matter where you go, there you are" | (916) 891-5281 ----------- Opinions expressed are subject to change without notice -----------