Question

表：SUBSCRIPTION

C_ID    SUB_YEAR    SUB_AMOUNT  DISCOUNT  PAID_AMOUNT
----------------------------------------------------
1      1            1250          0       0
2      2            2520          0       0
3      8            1459          0       0
4      6            7456          0       0
5      1            2584          0       0
6      3            2578          0       0
7      4            5478          0       0
8      5            5000          0       0

我需要的查询是，

如果sub_year是＆gt; 2然后他/她获得10％的折扣
和sub_year＆gt; 2或＆lt; = 3然后他/她获得20％的折扣
和sub_year＆gt; 3然后获得25％的折扣。

运行查询后，应使用值填充discount和paid_amount列。

我的查询是：

BEGIN
    FOR REC IN(SELECT  SUB_YEAR FROM SUBSCRIPTION)
    LOOP                                                                                  
        IF(REC.SUB_YEAR>1 AND REC.SUB_YEAR<=2) THEN
            UPDATE SUBSCRIPTION
            SET DISCOUNT = 10,P_AMOUNT= SUB_AMOUNT-SUB_AMOUNT*.1;
        ELSIF(REC.SUB_YEAR>2 AND REC.SUB_YEAR<=3) THEN
            UPDATE SUBSCRIPTION
            SET DISCOUNT = 20,P_AMOUNT= SUB_AMOUNT-SUB_AMOUNT*.2;
        ELSIF(REC.SUB_YEAR>3) THEN
            UPDATE SUBSCRIPTION
            SET DISCOUNT = 25,P_AMOUNT= SUB_AMOUNT-SUB_AMOUNT*.25;
        ELSE
            UPDATE SUBSCRIPTION
            SET DISCOUNT = 0,P_AMOUNT= SUB_AMOUNT;
        END IF;
    END LOOP;

    IF SQL%NOTFOUND THEN
        Dbms_output.put_line('No Employee Selected');
    ElsIF SQl%FOUND THEN
        Dbms_output.put_line('Employee Selected');

    END IF;
END;

问题出在所有行上，discount列填充了25％，paid_amount填充了sub_amount 25％的折扣。

Answer 1

您在查询中错过了WHERE条款，

BEGIN
     FOR REC IN(SELECT SUB_YEAR FROM SUBSCRIPTION)
     LOOP                                                                                  
          IF(REC.SUB_YEAR>1 AND REC.SUB_YEAR<=2) THEN
               UPDATE SUBSCRIPTION
               SET DISCOUNT = 10,p_amount= SUB_AMOUNT-SUB_AMOUNT*.1
               WHERE sub_year >1 and sub_year <= 2
          ELSIF(REC.SUB_YEAR>2 AND REC.SUB_YEAR<=3) THEN
               UPDATE SUBSCRIPTION
               SET DISCOUNT = 20,p_amount= SUB_AMOUNT-SUB_AMOUNT*.2
               WHERE SUB_YEAR>2 AND SUB_YEAR<=3;
          ELSIF(REC.SUB_YEAR>3) THEN
               UPDATE SUBSCRIPTION
               SET DISCOUNT = 25,p_amount= SUB_AMOUNT-SUB_AMOUNT*.25
               WHERE SUB_YEAR > 3
          ELSE
               UPDATE SUBSCRIPTION
               SET DISCOUNT = 0,p_amount = SUB_AMOUNT
               WHERE <condition>;
          END IF;
     END LOOP;
END;

或者您可以使用简单的UPDATE查询

来完成此操作

UPDATE subscription 
set discount = CASE WHEN sub_year >1 and sub_year <= 2 THEN  10 
                    WHEN sub_year >2 and sub_year <= 3 THEN  20 
                    WHEN sub_year >3 THEN  25
               ELSE 0 END, 
    p_amount = CASE WHEN sub_year >1 and sub_year <= 2 THEN  SUB_AMOUNT-SUB_AMOUNT*.1 
                    WHEN sub_year >2 and sub_year <= 3 THEN  SUB_AMOUNT-SUB_AMOUNT*.2
                    WHEN sub_year >3 THEN  SUB_AMOUNT-SUB_AMOUNT*.25
               ELSE SUB_AMOUNT END;

根据订阅年份给予折扣

1 个答案: