PL/SQL巢狀迴圈

2019-10-16 22:54:01

PL/SQL允許在另一個迴圈中使用一個迴圈。 以下部分顯示了幾個例子來說明這個概念。

PL/SQL中巢狀的基本`LOOP`語句的語法如下：

``````LOOP
Sequence of statements1
LOOP
Sequence of statements2
END LOOP;
END LOOP;
``````

PL/SQL中巢狀`FOR LOOP`語句的語法如下 -

``````FOR counter1 IN initial_value1 .. final_value1 LOOP
sequence_of_statements1
FOR counter2 IN initial_value2 .. final_value2 LOOP
sequence_of_statements2
END LOOP;
END LOOP;
``````

PL/SQL中巢狀的`WHILE LOOP`迴圈語句的語法如下：

``````WHILE condition1 LOOP
sequence_of_statements1
WHILE condition2 LOOP
sequence_of_statements2
END LOOP;
END LOOP;
``````

範例

``````SET SERVEROUTPUT ON SIZE 999999;
DECLARE
i number(3);
j number(3);
BEGIN
i := 2;
LOOP
j:= 2;
LOOP
exit WHEN ((mod(i, j) = 0) or (j = i));
j := j +1;
END LOOP;
IF (j = i ) THEN
dbms_output.put_line(i || ' is prime');
END IF;
i := i + 1;
exit WHEN i = 50;
END LOOP;
END;
/
``````

``````2 is prime
3 is prime
5 is prime
7 is prime
11 is prime
13 is prime
17 is prime
19 is prime
23 is prime
29 is prime
31 is prime
37 is prime
41 is prime
43 is prime
47 is prime

PL/SQL 過程已成功完成。
``````