Question

我正在尝试编写一个查询，该输出将输出为MONTH，YEAR。

当我写：

 select CAST( tbl.MONTH as varchar(2) ) + ', ' + CAST ( tbl.YEAR as varchar(4) ) as [DATE] 
 from TABLE as tbl

我得到输出为

    1,2014
    4,2014 (depending upon the input)

但是，现在，我想用JAN替换1，用DECRIL 12替换DEC

所以，我试着写一个案例陈述：

SELECT 
    case when tbl.MONTH ='1' 
    then ('JAN' + ', ' + CAST ( tbl.YEAR as varchar(4) )) as [DATE1]  
from TABLE as tbl

这会产生语法错误。谁能告诉我，我应该做什么？

Answer 1

case需要end：

SELECT (case when tbl.MONTH = '1' then 'JAN' + ', ' + CAST(tbl.YEAR as varchar(4) ))
        end) as [DATE1]
from TABLE tbl;

如果值存储为数字，则不要在常量值周围放置单引号。

Answer 2

您缺少关闭end声明所需的case：

case
when tbl.MONTH ='1'
then ('JAN' + ', ' + CAST ( tbl.YEAR as varchar(4) ))
end
as [DATE1] 
from TABLE as tbl

Answer 3

简单的方法是使用 Datename 内置函数。无需CASE statement对所有月份进行硬编码

SELECT Datename(mm, tbl.[MONTH]) + ', '
       + CONVERT(VARCHAR(10), tbl.YEAR) AS [DATE]
FROM   TABLE AS tbl

或者如果您使用的是sql server 2012

SELECT Choose(tbl.[MONTH], 'Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec')
       + ', ' + CONVERT(VARCHAR(10), tbl.YEAR) AS [DATE]
FROM   TABLE AS tbl

Answer 4

与普拉迪普的答案类似，但是使用了来自https://stackoverflow.com/a/188390/405180的方便的小DATENAME修正，并修剪为前3个字符：

SELECT UPPER(LEFT(Datename(MONTH , DateAdd( MONTH , tbl.[MONTH] , -1 )), 3)) + ', ' + CONVERT(VARCHAR(10), tbl.[YEAR]) AS [DATE]
FROM   TABLE AS tbl

TBH，我认为从性能的角度来看，您最好使用CASE tbl.[MONTH] WHEN 1 THEN 'JAN' WHEN ...方法。

SQL中的Case语句给出错误

4 个答案: