sql - 我需要为每个字段重写 case 语句吗？

Question

两列的 case 条件是相同的。在下面的语句中我使用了两次但是对于不同的列，有没有其他方法可以不重复条件两次？？

case [CPHIL_AWD_CD]
                     when ' ' then 'Not Applicable/ Not a Doctoral Student'
                     when 'X' then 'Not Applicable/ Not a Doctoral Student'
                     when 'N' then 'NO'
                     when 'Y' then 'YES'
                end as CPHIL_AWD_CD

              ,case [FINL_ORAL_REQ_CD] 
                     when ' ' then 'Not Applicable/ Not a Doctoral Student'
                     when 'X' then 'Not Applicable/ Not a Doctoral Student'
                     when 'N' then 'NO'
                     when 'Y' then 'YES'
                end as FINL_ORAL_REQ_CD

Answer 1

只需使用映射创建一个表(临时？)

CREATE TABLE [Constants]
(
    [ID] nvarchar(1) PRIMARY KEY,
    [Text] nvarchar(max)
)
INSERT INTO [Constants] VALUES (' ', 'Not Applicable/ Not a Doctoral Student')
INSERT INTO [Constants] VALUES ('X', 'Not Applicable/ Not a Doctoral Student')
INSERT INTO [Constants] VALUES ('N', 'No')
INSERT INTO [Constants] VALUES ('Y', 'Yes')

并执行内部连接

SELECT C1.Text AS CPHIL_AWD_CD, C2.Text AS FINL_ORAL_REQ_CD, ...
FROM YourTable T
INNER JOIN Constants C1 ON C1.ID = T.CPHIL_AWD_CD
INNER JOIN Constants C2 ON C2.ID = T.FINL_ORAL_REQ_CD