How To Check for an Index in Oracle
select count(*) from user_indexes where index_name = 'myIndex'
sqlplus won't support IF..., though, so you'll have to use anonymous PL/SQL blocks, which means EXECUTE IMMEDIATE to do DDL.
DECLARE i INTEGER;BEGIN SELECT COUNT(*) INTO i FROM user_indexes WHERE index_name = 'MYINDEX'; IF i = 0 THEN EXECUTE IMMEDIATE 'CREATE INDEX myIndex ...'; END IF;END;/Edit: as pointed out, Oracle stores unquoted object names in all uppercase.