SQL 當至少有一個值等於 value 然后設置為 value 的情況

Question

我正在嘗試通過查詢教授學位的不同值來更新表格。 faculty 表有一個 terminal degree 字段（值 Y 或 N）。 教授可以擁有多個學位，但如果至少有一行的最終學位 = Y，我想將該值設置為“Terminal”。 如果只有“N”的值，而沒有“Y”的值，那么我想將終端度數設置為“非終端”

下面是我目前擁有的代碼，但它不適用於擁有超過一個學位（Y 或 N 值）的教授

 UPDATE SNP_FACULTY_CENSUS SFC
    SET TERMINAL_DEGREE = (  
        Case
            WHEN EXISTS (SELECT DISTINCT(F.TERMINAL_DEGREE) 
                             FROM FACULTY F
                                left JOIN SNP_FACULTY_CENSUS S
                                ON F.PERSON_SKEY = S.PERSON_sKEY
                             )
                    THEN (SELECT  -- USE TERMINAL VALUE FROM FACULTY TABLE
                           CASE
                                 WHEN F.TERMINAL_DEGREE = 'Y' AND F.TERMINAL_DEGREE = ''--if at least ONE value equals Y
                                 THEN
                                     'Terminal'
                                WHEN F.TERMINAL_DEGREE = 'Y' -- if all values equal Y
                                 THEN 'Terminal'     
                                 WHEN F.TERMINAL_DEGREE = 'N' --if ALL values equal N    
                                 THEN
                                     'Not terminal'
                                 ELSE
                                     'Unknown'
                            END
                          FROM FACULTY F
                            left JOIN SNP_FACULTY_CENSUS S
                                ON F.PERSON_SKEY = S.PERSON_sKEY)                        
        
    
        END 
     ) 
    WHERE SFC.OIR_FALL_TERM = 'Fall 2019'
    ;

Answer 1

你必須使用不存在，下面的查詢應該有效，因為我沒有樣本數據，我無法測試它：

UPDATE SNP_FACULTY_CENSUS SFC
SET TERMINAL_DEGREE = (  
    Case
        WHEN EXISTS (SELECT DISTINCT F.TERMINAL_DEGREE 
                         FROM FACULTY F
                            left JOIN SNP_FACULTY_CENSUS S
                            ON F.PERSON_SKEY = S.PERSON_sKEY
                         )
                THEN (SELECT  -- USE TERMINAL VALUE FROM FACULTY TABLE
                       CASE
                             WHEN F.TERMINAL_DEGREE = 'Y' --if ONE value equals Y
                             THEN
                                 'Terminal'
                             WHEN F.TERMINAL_DEGREE = 'N' and not exists(select 1 from  FACULTY fa where F.PERSON_SKEY = fa.PERSON_sKEY and Fa.TERMINAL_DEGREE = 'N')--if ALL values equal N    
                             THEN
                                 'Not terminal'
                             ELSE
                                 'Unknown'
                        END
                      FROM FACULTY F
                        left JOIN SNP_FACULTY_CENSUS S
                            ON F.PERSON_SKEY = S.PERSON_sKEY)                        
    

    END 
 ) 
WHERE SFC.OIR_FALL_TERM = 'Fall 2019';