SQL CASE WHEN或IF ELSE IF

Question

在我想知道的情况下,如果我可以使用> <而不是定义每个案例,我有多个条件可以满足

在这种情况下,当信用评级小于3时,将插入单词"NO TRADE",然后大于3,小于5则为"POOR",依此类推等等

SELECT  ClientId, 
    FirstName,
    LastName,
    Gender,
    DateOfBirth,
    CreditRating,

        CASE CreditRating

            WHEN 0 THEN 'NO TRADE'
            WHEN 1 THEN 'NO TRADE'
            WHEN 2 THEN 'NO TRADE'
            WHEN 3 THEN 'POOR'
            WHEN 4 THEN 'POOR'
            WHEN 5 THEN 'AVARAGE'
            WHEN 6 THEN 'AVARAGE'
            WHEN 7 THEN 'GOOD'
            ELSE 'PERFECT' 

            END AS RATING

    FROM dbo.client

Answer 1

当然可以。

CASE 

WHEN CreditRating <= 2  THEN 'NO TRADE'
WHEN CreditRating  <= 4 THEN 'POOR'
WHEN CreditRating  <= 6 THEN 'AVARAGE'
WHEN CreditRating  = 7 THEN 'GOOD'

ELSE 'PERFECT' 

END AS RATING