sql - 有没有办法简化这个 TSQL Case 语句？

Question

是否有更简单的方法在 select 中编写 case 语句，或者这是唯一的方法？ 基本上如果 COL B 和 COL C 不为 NULL，则 col b - col c，如果其中一个为 null，则选择另一个。

SELECT
    COL_A AS [A],
    CASE WHEN NULLIF(COL_B, '') IS NOT NULL AND NULLIF(COL_C, '') IS NOT NULL
             THEN CONCAT(COL_B, ' - ', COL_C)
         WHEN NULLIF(COL_B, '') IS NULL AND NULLIF(COL_C, '') IS NOT NULL
             THEN COL_C
         WHEN NULLIF(COL_B, '') IS NOT NULL AND NULLIF(COL_C, '') IS NULL
             THEN COL_B
     END AS [B]

Answer 1

Basically if COL B AND COL C are not NULL, THEN col b - col c, if one is null, select the other.

使用CONCAT_WS :

SELECT CONCAT_WS(' - ', COL_B, COL_C) AS [B]

<强> db<>fiddle demo