在 SQL 服务器中将 NULL 值显示为透视列

Question

我需要在我下面的代码示例中将与 "animal type" 匹配的值的计数作为主元。不幸的是，我可能缺少 col2 ('a'、'b') 中的记录，但我需要计算它们在 'a'、'b' 或 null 中的动物类型。我需要将 NULL 旋转到具有该计数值的另一列中。我在查询结束时对所有旋转列进行求和，col2 中具有空值的列将与总数不匹配。

declare @testData   table   (   col1    varchar(10)
                            ,   col2    varchar(10)
                            )

insert into @testData   
values ('dog','a')
insert into @testData   
values ('cat','b')
insert into @testData   
values ('rabbit',null)

select * from @testData

select  
    pvt.col1        as  [Animal Type]
,   pvt.a           as  [A]
,   pvt.b           as  [B]
,   total.records   as  [Total Count]
from    (
            select 
                col1
            ,   col2
            ,   count(*)    as  records
            from    @testData   
            group by
                col1
            ,   col2
        )   as  s
pivot
        (
            sum(records)
            for     col2 in ([a], [b])
        )   as  pvt
join    (
            select 
                col1    
            ,   count(*)    as  Records
            from    @testData
            group by
                col1
        )   as  total               on  pvt.col1 = total.col1

Answer 1

使用 isnull 函数修改子查询中的 col2，如下所示：

select  
    pvt.col1        as  [Animal Type]
,   pvt.a           as  [A]
,   pvt.b           as  [B]
,   pvt.[NULL]      as  [NULL]
,   total.records   as  [Total Count]
from    (
            select 
                col1
            ,   ISNULL(col2,'NULL') col2
            ,   count(*)    as  records
            from    @testData   
            group by
                col1
            ,   col2
        )   as  s
pivot
        (
            sum(records)
            for     col2 in ([a], [b], [NULL])
        )   as  pvt
join    (
            select 
                col1    
            ,   count(*)    as  Records
            from    @testData
            group by
                col1
        )   as  total               on  pvt.col1 = total.col1

在 SQL 服务器中将 NULL 值显示为透视列

Show NULL value as pivoted column in SQL Server

sql-server

null

pivot