Alexander Barkov added a comment - 2018-09-21 02:58 - edited Sorry, can you clarify please? In the above script you have a REVERSE loop and direct bound order. It performs no iterations and produces no output. This looks correct. I just checked all four combinations and I think they give correct results: Direct loop, direct bound order (3 iterations as expected) SET SQL_MODE=ORACLE; delimiter // # DECLARE totalprice DECIMAL (12,2):= NULL ; loop_start INTEGER := 1; BEGIN FOR idx IN loop_start..3 LOOP SELECT idx; END LOOP; END ; // delimiter ; +-----+ | idx | +-----+ | 1 | +-----+ 1 row in set (0.01 sec)   +-----+ | idx | +-----+ | 2 | +-----+ 1 row in set (0.01 sec)   +-----+ | idx | +-----+ | 3 | +-----+ 1 row in set (0.01 sec)   Query OK, 0 rows affected (0.00 sec) Direct loop, reverse bound order (no iterations as expected) SET SQL_MODE=ORACLE; delimiter // # DECLARE totalprice DECIMAL(12,2):=NULL; loop_start INTEGER := 1; BEGIN FOR idx IN 3..loop_start LOOP SELECT idx; END LOOP; END; // delimiter ; Query OK, 0 rows affected (0.00 sec) Reverse loop, reverse bound order (3 iterations as expected) SET SQL_MODE=ORACLE; delimiter // # DECLARE totalprice DECIMAL (12,2):= NULL ; loop_start INTEGER := 1; BEGIN FOR idx IN REVERSE 3..loop_start LOOP SELECT idx; END LOOP; END ; // delimiter ; +-----+ | idx | +-----+ | 3 | +-----+ 1 row in set (0.00 sec)   +-----+ | idx | +-----+ | 2 | +-----+ 1 row in set (0.00 sec)   +-----+ | idx | +-----+ | 1 | +-----+ 1 row in set (0.00 sec)   Query OK, 0 rows affected (0.00 sec) Reverse loop, direct bound order (no iterations as expected) SET SQL_MODE=ORACLE; delimiter // # DECLARE totalprice DECIMAL (12,2):= NULL ; loop_start INTEGER := 1; BEGIN FOR idx IN REVERSE loop_start..3 LOOP SELECT idx; END LOOP; END ; // delimiter ; Query OK, 0 rows affected (0.00 sec)

Daniel Lee (Inactive) added a comment - 2018-09-21 12:37 The following is from the oracle documentation. If I am reading it correctly, your example 3 above should not produce results, while example 4 should. Thx https://docs.oracle.com/database/121/LNPLS/for_loop_statement.htm#LNPLS1515 [ REVERSE ] lower_bound .. upper_bound lower_bound and upper_bound must evaluate to numbers (see "Lower Bound and Upper Bound"). PL/SQL evaluates lower_bound and upper_bound once, when the FOR LOOP statement is entered, and stores them as temporary PLS_INTEGER values, rounding them to the nearest integer if necessary. If lower_bound equals upper_bound, the statements run only once. If lower_bound does not equal upper_bound when the FOR LOOP statement begins to run, then: If REVERSE is omitted: If lower_bound is greater than upper_bound, the statements do not run, and control transfers to the statement after the FOR LOOP statement. Otherwise, lower_bound is assigned to index, the statements run, and control returns to the top of the loop, where index is compared to upper_bound. If index is less than upper_bound, index is incremented by one, the statements run again, and control returns to the top of the loop. When index is greater than upper_bound, control transfers to the statement after the FOR LOOP statement. If REVERSE is specified: If upper_bound is less than lower_bound, the statements do not run, and control transfers to the statement after the FOR LOOP statement. Otherwise, upper_bound is assigned to index, the statements run, and control returns to the top of the loop, where index is compared to lower_bound. If index is greater than lower_bound, index is decremented by one, the statements run again, and control returns to the top of the loop. When index is less than lower_bound, control transfers to the statement after the FOR LOOP statement.

Alexander Barkov added a comment - 2018-12-26 04:21 Forgot to close. Was fixed in 10.3.11 on Nov 13.