Oracle 循环的三种写法

-- loop
-- 1. exit ... when 结束循环
DECLARE
v_value NUMBER(8) := -3;
BEGIN
<<value_loop>> -- 循环标记
LOOP
dbms_output.put_line('v_value = ' || v_value);
v_value := v_value+1;
EXIT value_loop WHEN v_value > 3;
END LOOP;
dbms_output.put_line('loop循环结束！');
END;

-- 2. if ... exit 结束循环
DECLARE
v_value NUMBER(8) := -3;
BEGIN
<<value_loop>>
LOOP
dbms_output.put_line('value:' || v_value);
v_value := v_value +1;
IF v_value > 3 THEN
dbms_output.put_line('value is larger than 3 ， current value is ' || v_value);
EXIT value_loop;
END IF;
END LOOP value_loop;
dbms_output.put_line('loop is end');
END;


-- while loop 本身有可以结束循环的条件

DECLARE
v_value NUMBER(8) := -3;
BEGIN
<<while_loop>>
WHILE(v_value < 4)
LOOP
dbms_output.put_line('value is ' || v_value);
v_value := v_value + 1;
END LOOP while_loop;
dbms_output.put_line('while loop is end');
END;


-- for...loop


BEGIN
FOR v_value IN -3..3 LOOP
dbms_output.put_line('value is ' || v_value);
END LOOP ;
dbms_output.put_line('for loop is end');
END;