通过使用case语句组合两个VarChar字段来为当前月份的SQL设置变量 [英] SQL Setting Variable for Current Year Month by Combining two VarChar fields using case statement

问题描述

我试图基于称为YEARMO的字段声明当前年份和月份的变量.

I am trying to declare a variable for the current year and month based on a field called YEARMO.

这是一个6个字符的varchar字段，前4个字符代表年份，后2个字符代表月份(例如，2018年2月为201802).

It's a 6 character varchar field with the first 4 characters representing the year and the next 2 characters representing the month (ex. February 2018 as 201802).

如果只有一个数字的月份(十月之前的任何月份)，我需要在月份变量前加0.当前代码返回"20182"，并希望它返回"201802".

I need the month variable to have a 0 in front of it if is a month that only has one digit (any month before October). Current code returns '20182' and would like it to return '201802'.

declare @current_month varchar(6)

set @current_month = CAST( year(getdate()) as varchar(4)) 
+ case when  len(CAST( month(getdate()) as varchar(2))) < 1 then '0' + 
CAST( month(getdate()) as varchar(2)) 
else CAST( month(getdate()) as varchar(2))
end

select @current_month;

推荐答案

您的代码过于复杂.使用right代替:

Your code is over complicated. Use right instead:

declare @current_month char(6)
set @current_month = CAST( year(getdate()) as varchar(4)) + right('00' + cast(month(getdate()) as varchar(2)), 2)
select @current_month;

结果:

201802

如果您确实要使用case，则应将1更改为2:

If you really want to use case instead, you should change the 1 to 2:

set @current_month = CAST( year(getdate()) as varchar(4)) + 
                     case when len(CAST(month(getdate()) as varchar(2))) < 2 then 
                     '0' + CAST( month(getdate()) as varchar(2)) else 
                     CAST( month(getdate()) as varchar(2)) end

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