簡化case語句

Question

下面是一個使用CASE我目前的更新語句。

UPDATE A 
SET OAP.GradeRange = 
     CASE WHEN (ABS(CAST(A.GRADE_FROM AS INT) - CAST(A.GRADE AS INT))) > 1 THEN 'Y' 
     ELSE 'N' END 
FROM dbo.Table A 

我如何下面添加一個額外的過濾器進入上述CASE？

where (grade_from <> 13 and GRADE <> 15) 
OR (grade_from <> 15 and GRADE <> 13) 

我想是這樣的：

UPDATE A 
    SET OAP.GradeRange = 
      CASE WHEN (ABS(CAST(A.GRADE_FROM AS INT) - CAST(A.GRADE AS INT))) AND (grade_from <> 13 and GRADE <> 15) OR (grade_from <> 15 and GRADE <> 13) > 1 THEN 'Y' 
      ELSE 'N' END 
    FROM dbo.Table A 

如果有什麼更好的方式來寫，請指教。謝謝。

Answer 1

試試這個。

我認爲> 1（大於1）應該在第一個條件後出現。

UPDATE A 
    SET OAP.GradeRange = 
      CASE WHEN (ABS(CAST(A.GRADE_FROM AS INT) - CAST(A.GRADE AS INT)) > 1) AND ((grade_from NOT IN ('13','15')) OR (GRADE NOT IN ('13','15'))) THEN 'Y' 
      ELSE 'N' END 
    FROM dbo.Table A 

Answer 2

你case缺少一個額外的括號，所以它不是做你想要什麼：

UPDATE A 
    SET OAP.GradeRange = 
      CASE WHEN (ABS(CAST(A.GRADE_FROM AS INT) - CAST(A.GRADE AS INT))) AND 
         ((grade_from <> 13 and GRADE <> 15) OR (grade_from <> 15 and GRADE <> 13) > 1) 
       THEN 'Y' 
       ELSE 'N' END 
    FROM dbo.Table A;