创建映射的有效方法

Question

我有 2 个 table 如下

CITY_A

ID	CODE	CITY
001	90	PARIS
002	90	PARIS
003	85	PARIS
004	60	SYDNEY
005	75	SYDNEY
006	75	SYDNEY

CITY_B

ID	CODE	CITY
001	IN	PA
002	OUT	PA
003	OUT	PA
004	IN	SYD
005	OUT	SYD
006	IN	SYD

两个 table 中的内容相同，但表示形式不同。我在这里有 2 个映射 CITY 列和 CODE 列。

映射 CITY_A

CODE	CITY	MEANING
90	PARIS	ACTIVE
85	PARIS	NOT_ACTIVE
60	SYDNEY	ACTIVE
75	SYDNEY	NOT_ACTIVE

映射 CITY_B

CODE	CITY	MEANING
IN	PA	ACTIVE
OUT	PA	NOT_ACTIVE
IN	SYD	ACTIVE
OUT	SYD	NOT_ACTIVE

现在我必须根据映射比较两个 table 并找到不匹配的地方。所以我的预期输出是

ID	CITY	RESULT
001	PARIS	MATCH
002	PARIS	MISMATCH
003	PARIS	MATCH
004	SYDNEY	MATCH
005	SYDNEY	MATCH
006	SYDNEY	MISMATCH

目前我正在使用 CASE 和温度 table。太大了。

SELECT A.ID , CASE WHEN A.CODE = 90 AND A.CITY = 'PARIS' THEN 'ACTIVE' 
                   WHEN A.CODE = 85 AND A.CITY = 'PARIS' THEN 'NOT_ACTIVE' 
               -- FOR OTHER CITIES
               END AS A.CODE_MEANING,
               CITY
INTO #TEMP_CITY_A              
FROM CITY_A A

SELECT B.ID,CASE WHEN B.CODE = 'IN'  AND B.CITY='PA' THEN 'ACTIVE'
                   WHEN B.CODE = 'OUT'  AND B.CITY='PA' THEN 'NOT_ACTIVE' 
              -- FOR OTHER CITIES
            END AS B.CODE_MEANING,
            CASE WHEN B.CITY = 'PA' THEN 'PARIS' 
                 WHEN B.CITY = 'SYD' THEN 'SYDNEY'
             -- FOR OTHER CITIES
            END AS CITY
 INTO #TEMP_CITY_B              
 FROM CITY_B B

SELECT A.ID ,A.CITY, 
     CASE WHEN A.CODE_MEANING!=B.CODE_MEANING THEN 'MISMATCH' ELSE 'MATCH' END AS RESULT
FROM #TEMP_CITY_A A
JOIN #TEMP_CITY_B B ON A.ID = B.ID AND A.CITY = B.CITY

哪种方法最有效？

Answer 1

这是一种使用 CTE 和 table 映射 tables:

值构造函数来实现所需结果的可能方法

WITH CITY_A_MAP AS (
  SELECT * FROM (
    VALUES(90, 'PARIS', 'Active'),(85, 'PARIS', 'Not_Active'),(60, 'SYDNEY', 'Active'),(75, 'SYDNEY', 'Not_Active')
  ) AS MAP(CODE, CITY, MEANING)
),
CITY_B_MAP AS (
  SELECT * FROM (
    VALUES ('IN', 'PA', 'Active'),('OUT', 'PA', 'Not_Active'),('IN', 'SYD', 'Active'),('OUT', 'SYD', 'Not_Active')
  ) AS MAP(CODE, CITY, MEANING)
)
SELECT A.ID, A.CITY,
       CASE WHEN MA.MEANING = MB.MEANING THEN 'MATCH' ELSE 'MISMATCH' END AS RESULT
FROM CITY_A A
JOIN CITY_A_MAP MA ON MA.CITY = A.CITY AND MA.CODE = A.CODE
JOIN CITY_B B ON B.ID = A.ID
JOIN CITY_B_MAP MB ON MB.CITY = B.CITY AND MB.CODE = B.CODE
ORDER BY A.ID

输出：

ID  CITY    RESULT
1   PARIS   MATCH
2   PARIS   MISMATCH
3   PARIS   MATCH
4   SYDNEY  MATCH
5   SYDNEY  MATCH
6   SYDNEY  MISMATCH

Demo on dbfiddle

创建映射的有效方法

Efficient way for creating mapping

sql

sql-server

sql-server-2012