Question

如何使用case语句根据列中包含的值来命名列。我有一个俱乐部的成员，可以注册白金，金，银和铜会员。数据存储在名为CUST_MBR_INFO的表中。我希望能够通过成员资格类型和CUST_ID关联客户。是否可以在组合的单个查询中显示如下信息？我的查询用于获取单个标签，但我真的想使用单个查询。所有标签都应该可用，CUST_IDs落在正确的标题中，以便打印在表格中。

PLATINUM_CUSTOMER GOLD_CUSTOMER SILVER_CUSTOMER BRONZE_CUSTOMER

1222                   -            -                        -
-                     3122              -                        -

会员类型基于2列的值

--CUST_ID 1222
--PLATINUM_CUSTOMER
SELECT CUST_ID,PROD_CODE AS PLATINUM_CUSTOMER FROM CUST_MBR_INFO
WHERE PROD_CATG_VAL = 'PLATINUM'
AND M_TYP_CDE = '1'



--CUST_ID 3122
--GOLD
SELECT CUST_ID,PROD_CODE AS GOLD_CUSTOMER FROM CUST_MBR_INFO
WHERE PROD_CATG_VAL = 'GOLD' 
AND M_TYP_CDE = '2'

--CUST_ID 3422
--SILVER
SELECT CUST_ID,PROD_CODE AS SILVER_CUSTOMER FROM CUST_MBR_INFO
WHERE PROD_CATG_VAL = 'SILVER'
AND M_TYP_CDE = '3'

--CUST_ID 94344
--BRONZE_CUSTOMER
SELECT CUST_ID,PROD_CODE AS BRONZE_CUSTOMER FROM CUST_MBR_INFO
WHERE PROD_CATG_VAL = 'BRONZE'
AND M_TYP_CDE = '4

Answer 1

如果我理解正确，一种方法是使用UNION ALL：

SELECT CUST_ID as Platinum, NULL as Gold, NULL as Silver, NULL as Bronze
FROM CUST_MBR_INFO
WHERE PROD_CATG_VAL = 'PLATINUM' AND M_TYP_CDE = '1'
UNION ALL
SELECT NULL as Platinum, CUST_ID as Gold, NULL as Silver, NULL as Bronze
FROM CUST_MBR_INFO
WHERE PROD_CATG_VAL = 'GOLD' AND M_TYP_CDE = '2'
UNION ALL
SELECT NULL as Platinum, NULL as Gold, CUST_ID as Silver, NULL as Bronze
FROM CUST_MBR_INFO
WHERE PROD_CATG_VAL = 'SILVER' AND M_TYP_CDE = '3'
UNION ALL
SELECT NULL as Platinum, NULL as Gold, NULL as Silver, CUST_ID as Bronze
FROM CUST_MBR_INFO
WHERE PROD_CATG_VAL = 'BRONZE' AND M_TYP_CDE = '4';

还有其他方法可以实现这一点，但这对您的用例来说似乎最简单。

Oracle SQL根据条件值选择列别名

1 个答案: