在Access中更新查询 - CASE WHEN

Question

我是SQL代码的新手，我还在学习。

我有一张表Gas_Data，其中我有一些日子，因为某个事件是DATEDIFF，我需要对这个年龄段进行调整，我正在努力编写所需的编码。

我尝试创建另一个表作为参考，并尝试从示例中进行各种不同的编码。

“查询表达式'CASE中的语法错误（缺少运算符）

UPDATE Gas_Data

SET MONTH_BAND =

CASE

WHEN DATEDIFF < 29 THEN '00. Up to 1 Month'
WHEN DATEDIFF BETWEEN 30 AND 60 THEN '01. 1 to 2 Months'
WHEN DATEDIFF BETWEEN 61 AND 60 THEN '02. 2 to 3 Months' 
WHEN DATEDIFF BETWEEN 91 AND 60 THEN '03. 3 to 4 Months' 
WHEN DATEDIFF BETWEEN 121 AND 60 THEN '04. 4 to 5 Months' 
WHEN DATEDIFF BETWEEN 151 AND 60 THEN '05. 5 to 6 Months' 
WHEN DATEDIFF BETWEEN 181 AND 60 THEN '06. 6 to 7 Months' 
WHEN DATEDIFF BETWEEN 211 AND 60 THEN '07. 7 to 8 Months' 
WHEN DATEDIFF BETWEEN 241 AND 60 THEN '08. 8 to 9 Months' 
WHEN DATEDIFF BETWEEN 271 AND 60 THEN '09. 9 to 10 Months' 
WHEN DATEDIFF BETWEEN 301 AND 60 THEN '10. 10 to 11 Months' 
WHEN DATEDIFF BETWEEN 331 AND 60 THEN '11. 11 to 12 Months' 
WHEN DATEDIFF BETWEEN 366 AND 60 THEN '12. 12 to 18 Months' 
WHEN DATEDIFF BETWEEN 546 AND 60 THEN '13. 18 to 24 Months' 
WHEN DATEDIFF BETWEEN 731 AND 60 THEN '14. 24 to 30 Months' 
WHEN DATEDIFF BETWEEN 911 AND 60 THEN '15. 30 to 36 Months' 
WHEN DATEDIFF >= 1096 THEN '16. > 36 Months'
ELSE 'NO_AGE_BAND' END AS UNBILLED_MONTHS 

END


MONTH_BAND
00. Up to 1 Month
01. 1 to 2 Months
02. 2 to 3 Months
03. 3 to 4 Months
04. 4 to 5 Months
05. 5 to 6 Months
06. 6 to 7 Months
07. 7 to 8 Months
08. 8 to 9 Months
09. 9 to 10 Months
11. 11 to 12 Months
12. 12 to 18 Months
13. 18 to 24 Months
14. 24 to 30 Months
15. 30 to 36 Months
16. > 36 Months

Answer 1

MS Access使用switch()代替：

UPDATE Gas_Data
    SET MONTH_BAND = SWITCH(DATEDIFF < 29, "00. Up to 1 Month"
                            DATEDIFF BETWEEN 30 AND 60, "01. 1 to 2 Months"
                            . . .
                            DATEDIFF >= 1096, "16. > 36 Months"
                            1=1, "NO_AGE_BAND");

MS Access也更喜欢字符串分隔符的双引号。