>What is the fastest way to search through a file to find a substring within a field? I know you can
>

>set filter to 'xyz" $ yourfield
>go top
>

>or an SQL Select equivalent, but in a file where there are thousands of records, it takes a long time, specially on a network...
>Is there a quicker way?

If you have a limited set of sub-strings to search for, you can

index on 'xyz" $ yourfield tag xyz_ binary

Then any search will get optimized