Question

我得到了以下Patients表。

HospitalId INT,
GenderId BIT,
Age TINYINT,
DiseaseId SMALLINT

GenderId = 0是男性

GenderId = 1是女性

HospitalA的HospitalId 0

HospitalB有HospitalId 1

这是我想要产生的输出：

DiseaseId | HospitalA_Male_18-30 | HospitalA_Male_31-40 |
---------------------------------------------------------
0         |   (count here)       |   (count here)       |
1         |   (count here)       |   (count here)       |
2         |   (count here)       |   (count here)       |
3         |   (count here)       |   (count here)       |

（专栏继续）

HospitalA_Female_18-30 | HospitalA_Female_31-40 |
-------------------------------------------------
    (count here)       |     (count here)       |
    (count here)       |     (count here)       |
    (count here)       |     (count here)       |
    (count here)       |     (count here)       |

（专栏继续）

HospitalB_Male_18-30 | HospitalB_Male_31-40 |
---------------------------------------------
    (count here)     |     (count here)     |
    (count here)     |     (count here)     |
    (count here)     |     (count here)     |
    (count here)     |     (count here)     |

（专栏继续）

HospitalB_Female_18-30 | HospitalB_Female_31-40 |
-------------------------------------------------
    (count here)       |     (count here)       |
    (count here)       |     (count here)       |
    (count here)       |     (count here)       |
    (count here)       |     (count here)       |

（结果集中的9列）

因此，您可以看到我实际上需要计算每种疾病，每个特定组中有多少患者（按医院，按性别和年龄分类）。

如何在T-SQL中完成此类分组（最有效）？

Answer 1

请试试这个

SELECT  
    DiseaseId,
    SUM(CASE WHEN HospitalId = 0 AND GenderId=0 AND (Age BETWEEN 18 AND 30)  THEN 1 ELSE 0 END) AS [HospitalA_Male_18-30],
    SUM(CASE WHEN HospitalId = 0 AND GenderId=0 AND (Age BETWEEN 31 AND 40)  THEN 1 ELSE 0 END) AS [HospitalA_Male_31-40],  
    SUM(CASE WHEN HospitalId = 0 AND GenderId=1 AND (Age BETWEEN 18 AND 30)  THEN 1 ELSE 0 END) AS [HospitalA_Female_18-30],    
    ......  
FROM   Patients 
GROUP BY DiseaseId
ORDER BY DiseaseId

Answer 2

您可以使用数据透视查询来执行此操作：

select * from 
(
  select diseaseid, 
         'Hospital'
         + case hospitalid when 0 then 'A' when 1 then 'B' end
         + '_'
         + case genderid when 1 then 'Female' else 'Male' end
         + '_'
         + case when age between 18 and 30 
              then '18-30' 
              else (case when age between 31 and 40 then '31-40' end) 
              end Title,
         1 Cnt
  from Patients
  where age between 18 and 40
) t
pivot (
  count (Cnt) for Title in (
    [HospitalA_Male_18-30],   [HospitalA_Male_31-40],
    [HospitalA_Female_18-30], [HospitalA_Female_31-40],
    [HospitalB_Male_18-30],   [HospitalB_Male_31-40],
    [HospitalB_Female_18-30], [HospitalB_Female_31-40]
  )
) as Q

<强>更新

作为上述解决方案的开发，您还可以将名称部分从CASE表达式移动到它们自己的虚拟表，并将Patients表连接到它们：

;with
hospital (hospitalid, hospitalname) as (
  select 0, 'HospitalA' union all
  select 1, 'HospitalB'
),
gender (genderid, gendername) as (
  select 0, 'Male' union all
  select 1, 'Female'
),
agerange (agefrom, ageto) as (
  select 18, 30 union all
  select 31, 40
)
select * from 
(
  select p.diseaseid, 
         h.hospitalname + '_' + g.gendername + '_'
         + rtrim(a.agefrom) + '-' + rtrim(a.ageto) as Title,
         1 Cnt
  from Patients p
    inner join hospital h on p.hospitalid = h.hospitalid
    inner join gender   g on p.genderid   = g.genderid
    inner join agerange a on p.age between a.agefrom and a.ageto
  where p.age between 18 and 40
) t
pivot (
  count (Cnt) for Title in (
    [HospitalA_Male_18-30],   [HospitalA_Male_31-40],
    [HospitalA_Female_18-30], [HospitalA_Female_31-40],
    [HospitalB_Male_18-30],   [HospitalB_Male_31-40],
    [HospitalB_Female_18-30], [HospitalB_Female_31-40]
  )
) as Q

添加子选择和连接的开销弥补了更容易的维护：

（meta）数据部分与逻辑部分分开;
根据需要，名称部分列表更方便扩展;
如果您需要更改目标列名称的格式，则更容易修改串联表达式。

如何计算复杂年龄/性别/等群体的人？

2 个答案: