在列分配中跳过 NULL 值

Question

有一个包含地址信息的数据库表

+--------------------------------------------------------------+
| name1       | name2 | name3 | street        | zip     | city |
+--------------------------------------------------------------+
| 'Some name' | NULL  | ''    | 'Some street' | '12345' | NULL |
+--------------------------------------------------------------+

因此某些字段可能为 NULL 或空。

现在我要选择

SELECT
  name1,  /* 'Some name' */
  name2,  /* NULL */
  name3,  /* '' */
  street, /* 'Some street' */
  zip,    /* '12345' */
  city,   /* NULL */

  adr1,   /* Should contain 'Some name' */
  adr2,   /* Should contain 'Some street' */
  adr3,   /* Should contain '12345' */
  adr4,   /* NULL */
  adr5,   /* NULL */
  adr6    /* NULL */
FROM
 adr

其中adr1 到6 代表信头行，应按name1、name2、name3、street、street、zip、city 的顺序填充，但应跳过 NULL 或赋值时为空值。

有人知道如何实现这一目标吗？

Answer 1

这有点混乱，并且依赖于您有一个 ID 列，但是，我认为这就是您所追求的：

WITH CTE AS(
    SELECT S.YourID,
           S.name1,
           S.name2,
           S.name3,
           S.street,
           S.zip,
           S.city,
           NULLIF(V.Adr,'') AS Adr,
           Line,
           ROW_NUMBER() OVER (PARTITION BY YourID, CASE WHEN NULLIF(V.Adr,'') IS NULL THEN 1 ELSE 0 END ORDER BY Line) AS RN
    FROM (VALUES(1, 'Some name',CONVERT(varchar(10),NULL),'','Some street','12345',CONVERT(varchar(10),NULL))) S(YourID,name1,name2,name3,street,zip,city)
         CROSS APPLY(VALUES(name1,1),(name2,2),(name3,3),(street,3),(zip,4),(city,5)) V(Adr,Line))
SELECT C.YourID,
       MAX(C.name1) AS name1,
       MAX(C.name2) AS name2,
       MAX(C.name3) AS name3,
       MAX(C.street) AS street,
       MAX(C.zip) AS zip,
       MAX(C.city) AS city,
       MAX(CASE WHEN C.RN = 1 THEN C.Adr END) AS Adr1,
       MAX(CASE WHEN C.RN = 2 THEN C.Adr END) AS Adr2,
       MAX(CASE WHEN C.RN = 3 THEN C.Adr END) AS Adr3,
       MAX(CASE WHEN C.RN = 4 THEN C.Adr END) AS Adr4,
       MAX(CASE WHEN C.RN = 5 THEN C.Adr END) AS Adr5,
       MAX(CASE WHEN C.RN = 6 THEN C.Adr END) AS Adr6
FROM CTE C
WHERE C.Adr IS NOT NULL
GROUP BY C.YourID;