Question

我在db2的选择查询中有多行，它们在sum函数内使用带有AND的CASE。在mySQL上可以正常使用，但由于“与”而不再起作用。

我不能同时使用该关键字和case语句吗？我正在尝试将这些东西作为一个整体来汇总，而找不到IBM对此的直接解决方案。

原始查询：

select  
    sum(case when legtype1 = 2 then 1 else 0 end and answered = 1) as total_inbound
    , sum(case when legtype1 = 2 then 1 else 0 end and answered = 0) as total_missed
    , ROUND(COALESCE(100.00 * sum(case when legtype1 = 2 and answered = 1 then 1 end)/
        sum(case when legtype1 = 2 then 1 end), 100),2) as percent_answered

from table1;

我尝试过

 sum(case when legtype1 = 2 then 1 else 0 end, case when answered = 1 then 1 else 0 end)

但这也不正确。我需要根据两个条件都满足来进行求和，在DB2中我应该采用其他方法吗？我认为会有一种别名化每个条件的方法，但是我还没有找到任何东西。

Answer 1

我认为DB / 2对其条件更为严格，不要让AND和int和条件，而应将结果作为SUM的参数。本质上，这与AND无关-如果您尝试对布尔值求和，例如，应该会遇到相同的问题。 SUM(answered = 1)

您应该能够在AND表达式内推CASE，像这样：

select  
    sum(case when legtype1 = 2 and answered = 1 then 1 else 0 end) as total_inbound
,   sum(case when legtype1 = 2 and answered = 0 then 1 else 0 end) as total_missed
,   ROUND(COALESCE(100.00 * sum(case when legtype1 = 2 and answered = 1 then 1 end)/
    sum(case when legtype1 = 2 then 1 end), 100),2) as percent_answered

from table1;

Answer 2

出于兴趣，您可以将Db2 11.1.2.2版中的BOOLEAN值相加

drop  table table1;
create table table1(legtype1 int, answered int);
insert into table1 values (2,1),(2,1),(null, null),(2,0);
select
    sum(legtype1 = 2 and answered = 1) as total_inbound
,   sum(legtype1 = 2 and answered = 0) as total_missed
from table1;

 TOTAL_INBOUND TOTAL_MISSED
 ------------- ------------
             2            1

db2在SUM中将AND与CASE结合使用

2 个答案: