Matches versus substring

Hi all IDS V7.31, HP-UX10.20 The following query is failing when the substring method is used, but works when the MATCHES equivalent is coded in. I've seen this on SE before, caused by a duff index, but I've done oncheck -cI on the tables involved in this query, finding no errors. Any clues? (both dbaccess and isql produce the same results; the sqexplain plans for both methods are identical)) SELECT cl.clmainid_keynme, cl.personal_sex, cl.personal_dob, cl.address_add1, cl.address_add2, cl.address_add3, cl.address_add4, cl.address_city, cl.address_cntry, cl.address_postcd, cl.clmainid_ref, c.policy_number, cl.status_code, c.status_code ,c.polst_id_code FROM contract c, clientmain cl WHERE c.addressee_ref = 430374 AND c.addressee_ref = cl.clmainid_ref AND c.master_id_ref < 10 AND c.status_code IN ('active','not_active') AND cl.master_id_ref < 10 AND cl.status_code IN ('active','not_active') AND c.plan__id_code MATCHES 'PRP*' AND c.polst_id_code MATCHES 'IF*' <----- THIS WORKS (1 row returned) --- AND c.polst_id_code[1,2] = "IF" <----- THIS RETURNS NO ROWS -- Malc_p -- XS2Mail: Check your mail anywhere http://www.xs2mail.com/