SQL大小写，当至少一个值等于值然后设置为值

如何解决SQL大小写，当至少一个值等于值然后设置为值

我正在尝试通过查询教授学位的不同值来更新表格。教职员工表具有终极学位字段（值Y或N）。教授可以拥有一个以上的学位，但是如果至少有一行他们的终极学位= Y，我想将其值设置为“ Terminal”。如果仅存在“ N”值，而没有“ Y”值，那么我想将终端度设置为“非终端”

下面是我目前拥有的代码，但不适用于一个以上学位（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'
    ;

解决方法

您必须使用不存在，下面的查询应该可以使用，因为我没有示例数据，所以无法对其进行测试：

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';