Thanks Chris,

I can not afford "SELECT * FROM tableA" since this query runs too often and tableA is too big.

I did figure out a way to do it though with rather small cost (to memory):

SELECT tableB
INDEX ON nRecno TAG nRecno
SELECT (some fields) FROM tableA ;
   WHERE SEEK(RECNO(), "tableB", "nRecno")

This works well!

Thank you!

Jun