在PL/SQL中,有三種循環結構:(1)簡單循環;(2)while循環;(3)for循環
1.簡單循環
LOOP
sequence_of_statement;
exit [when condition]; --exit很重要,它是用來終止循環的,如果沒有會陷入死循環。
END LOOP;
for example:
declare
v_counter BINARY_INTERGER :=1;
BEGIN
LOOP
INSERT INTO user values(v_Counter,'Loop index' );
v_counter = v_counter + 1;
EXIT WHEN v_counter>50;
END LOOP;
END;
2.while循環
WHILE condition LOOP
sequence_of_statement;
END LOOP;
for example:
declare
v_counter BINARY_INTERGER :=1;
BEGIN
WHILE v_counter<=50 LOOP
INSERT INTO user values(v_Counter,'Loop index' );
v_counter = v_counter + 1;
END LOOP;
ENDL;
3.for循環
FOR loop-counter in (reverse) low_bound..high_bound LOOP
sequence_of_statement
END LOOP;
for example:
BEGIN
FOR v_counter IN 1..50 LOOP
INSERT INTO user values(v_counter,'LOOP_INDEX');
END LOOP;
END;