Question

我试图添加到现有的SQL查询以输出＆＃34; No Data Found＆＃34;如果整个查询为null。

我想显示＆＃34;没有找到数据＆＃34;而不是显示空白输出。

数据库我正在编写SQL查询是针对InterSystems Cache的。任何帮助是极大的赞赏。

这是我正在使用

的查询

SELECT Case
when sn.1_code =  1 then 'Attended  -- ' || 
                          sn.mult_1 || 
                          'and'  ||  
                          sn.dict_2 ||  
                          ' also acted with ' ||  
                          sn.dict_3 || 
                          '.'  
 when sn.1_code =  3 then 'left because ' ||
                          sn.mult_2 ||
                          '.' 
 when sn.dict_1 =  2 then 'Went home' 
 when sn.dict_1 = 24 then 'Canceled' END AS 'Attendance',
sn.dict_2 AS 'Continue'
FROM db.sn
Where sn.dict_2 = 123

如果查询是基于where子句的，那么输出应显示文本＆＃34;今天没有找到123的数据＆＃34;而不是在我的系统上显示空白屏幕的内容。如果不是isnull那么将显示数据。

IF Query isnull output should show
NO DATA FOUND FOR 123 TODAY

If Query not isnull output should show 
Attendance:                                 Continue:
Attended today. Also Acted with respect     Great
Left because not feeling well               Excussed
Went Home                                   Not Excused

由于

Answer 1

CASE围绕IsNull：

SELECT 
   IsNull(
      CASE
         when sn.1_code =  1 
            then 'Attended  -- ' || 
                 sn.mult_1 || 
                 'and'  ||  
                 sn.dict_2 ||  
                 ' also acted with ' ||  
                 sn.dict_3 || 
                 '.'  
         when sn.1_code =  3 
            then 'left because ' ||
                 sn.mult_2 ||
                 '.' 
         when sn.dict_1 =  2 
            then 'Went home' 
         when sn.dict_1 = 24 
            then 'Canceled' 
      END , 'No Data Found' )  AS 'Attendance'
FROM db.sn

SQL查询，如果选择条件为null输出为文本

1 个答案: