Hello,

has anyone an idea, why Firebird 2.1.2 does not use the index in Case 2? Using "LIKE" instead of "STARTING WITH" doesn't change anything. Without the "JOIN Ort" the Index is used.

Thanks!
Roland


CASE 1: "="
===========

SELECT P.ID Person
FROM Person P
JOIN Strasse S ON S.ID = P.STRASSE
JOIN Ort O ON O.ID = S.Ort
WHERE P.UFirma='GU'

PLAN JOIN (P INDEX (PERSON_UFIRMA), S INDEX (RDB$PRIMARY26), O INDEX (RDB$PRIMARY22))

CASE 2: "STARTING WITH"
=======================

SELECT P.ID Person
FROM Person P
JOIN Strasse S ON S.ID = P.STRASSE
JOIN Ort O ON O.ID = S.Ort
WHERE P.UFirma STARTING WITH 'GU'

PLAN JOIN (O NATURAL, S INDEX (RDB$FOREIGN29), P INDEX (PERSON_UFIRMA, RDB$FOREIGN58))