我想计算指定年份学生表中的男性、女性和学生总数。我希望结果可以以以下形式显示：
====================================
| Label | Value | Year |
====================================
| Male | 0 | 2013 |
| Female | 23 | 2013 |
| Total | 23 | 2013 |
====================================
如果指定年份没有男性/女性匹配，则查询应显示 0。知道我怎样才能做到这一点吗？
提前致谢
考虑以下查询：
select
max(registeredYear) as year,
count(case when gender='Male' then 1 end) as male_cnt,
count(case when gender='Female' then 1 end) as female_cnt,
count(*) as total_cnt
from student
where registeredYear = 2013
group by registeredYear;
结果将是这样的：
Year male_cnt female_cnt total_cnt
---- -------- ---------- ---------
2013 0 23 23
您可以将此结果转换为您想要的形式。如果您想在查询中执行此操作，则可以这样做：
with t as (
select
max(registeredYear) as year,
count(case when gender='Male' then 1 end) as male_cnt,
count(case when gender='Female' then 1 end) as female_cnt,
count(*) as total_cnt
from student
where registeredYear = 2013
group by registeredYear)
select 'Male', male_cnt as male, year from t
union all
select 'Female', female_cnt as male, year from t
union all
select 'Total', total_cnt as male, year from t
;
你应该使用：
select name, COUNT(*)as tot,
COUNT(case when details.gender='male' then 1 end) as male,
COUNT(case when details.gender='female' then 1 end) as female
from details group by name
SELECT
SUM(CASE WHEN gender = 'Male' THEN 1 ELSE 0 END) as MaleCount,
SUM(CASE WHEN gender = 'Female' THEN 1 ELSE 0 END) as FemaleCount,
COUNT(*) as TotalCount
FROM student
WHERE registeredYear = 2013
您的要求看起来很简单，但它有两个复杂性。第一个是一行是其他两行的摘要。这建议在查询中使用rollup或。grouping sets
第二个是即使您没有数据也需要有值。这建议使用“驱动程序”子查询。这样的子查询在分配值之前定义输出中的所有行。您将驱动程序表与left outer join.
一个未说明的要求可能是只提及一年一次。
以下查询方法将年度的最终表格放在一起。然后左加入摘要，从那里提取值（如果有）：
with year as (
select 2013 as Year
)
select driver.label, coalesce(s.value, 0) as Value, driver.Year
from ((select 'Male' as label, year from year
) union all
(select 'Female' as label, year from year
) union all
(select 'Total' as label, year from year
)
) driver left outer join
(select coalesce(Gender, 'Total') as Gender, year.year, count(*) as value
from Students cross join year
group by Gender with Rollup
) s
on driver.year = s.year;
这假设性别表示为“男性”和“女性”，并且year数据中有一个称为列的列（没有样本输入或表格格式，人们必须猜测列名和样本值）。
我相信这与您只需通过学生表即可获得的效率一样高。只需根据需要更改 CTE 年份中的年份。
with
year as
(
select '2013' year
),
gender as (
select 'Male' gender
union all
select 'Female' gender
)
select coalesce(g.gender,'Total') "Label",
count(s.gender) "Value",
y.year "Year"
from gender g
cross join year y
left join student s
on s.gender = g.gender
and s.year = y.year
group by grouping sets( (g.gender, y.year), (y.year) )
order by case g.gender when 'Male' then 1 when 'Female' then 2 else 3 end
;
完全标准化的数据模型可能同时具有学年和性别表，因此不需要 CTE。（除非您真的想返回没有任何数据的年份的行）
这是一个没有学生 ID 和姓名的简单 sqlfiddle演示，因为它们与手头的问题无关。
像这样的东西：
select 'Male' as Label, count(gender) as Value from student where gender= 'Male'
union (
select 'Female' as Label, count(gender) as Value from student where gender= 'Female' )
union (
select 'Total' as Label, count(gender) as Value from student )
这是另一个变体，使用 UNPIVOT。这个专门搜索男性和女性，所以它不像我的另一个那样灵活（因为你需要对每个性别进行硬编码）。但这可能是最有效的。
WITH AllYears (RegisteredYear) AS
(
--SELECT DISTINCT RegisteredYear
--FROM Student
--...OR...
SELECT 2014
)
, GenderAndYearCounts AS
(
SELECT RegisteredYear
, SUM(CASE Gender WHEN 'MALE' THEN 1 ELSE 0 END) MaleCount
, SUM(CASE Gender WHEN 'FEMALE' THEN 1 ELSE 0 END) FemaleCount
, COUNT(*) YearCount
FROM Student
GROUP BY RegisteredYear
)
, GenderAndYearCountsForAllYears AS
(
SELECT AllYears.RegisteredYear
, ISNULL(MaleCount, 0) AS MaleCount
, ISNULL(FemaleCount, 0) AS FemaleCount
, ISNULL(YearCount, 0) AS YearCount
FROM AllYears
LEFT JOIN GenderAndYearCounts ON GenderAndYearCounts.RegisteredYear = AllYears.RegisteredYear
)
SELECT Label, Value, RegisteredYear
FROM
(
SELECT RegisteredYear, MaleCount AS Male, FemaleCount AS Female, YearCount AS Total
FROM GenderAndYearCountsForAllYears
) allCounts
UNPIVOT
(
Value FOR Label IN (Male, Female, Total)
) unpivotted
所有的性别，然后是所有的年份，然后是计数：
declare @Year int
set @Year = 2014
select labels.label,
counts.cnt,
@Year as registeredYear
from
(select 'Male' as label, 1 as sortOrder
union all
select 'Female', 2
union all
select 'All', 3) as labels
left join
(select gender,
count(1) cnt
from student
where registeredYear = @Year
group by gender) as counts
on labels.label = counts.gender
order by labels.sortOrder
这对我有用。但是，在没有数据的年份里，它仍然无法为 M 和 F 显示 0 ：
Select * from
(
SELECT isnull (SUM(CASE WHEN gender = 'M' THEN 1 ELSE 0 END),0) as Male,
isnull(SUM(CASE WHEN gender = 'F' THEN 1 ELSE 0 END),0) as Female,
registeredYear as 'year'
FROM student
WHERE registeredDate.Year = 2013 //could be a variable
group by registeredYear
) as s
UNPIVOT
(
value FOR gender IN (Male, Female)
) Sub
试试这个，假设 Gender 或 RegisteredYear 中没有空值：
WITH AllYears AS
(
SELECT RegisteredYear
FROM Student
GROUP BY RegisteredYear
)
, AllGenders AS
(
SELECT Gender
FROM Student
GROUP BY Gender
)
, AllGendersAndYears AS
(
SELECT Gender, RegisteredYear
FROM AllGenders, AllYears
)
SELECT Gender, RegisteredYear, CountForGenderAndYear
FROM AllGendersAndYears
CROSS APPLY
(
SELECT COUNT(*) AS CountForGenderAndYear
FROM Student
WHERE Student.Gender = AllGendersAndYears.Gender
AND Student.RegisteredYear = AllGendersAndYears.RegisteredYear
) countForGenderAndYear
UNION ALL
SELECT 'Total', AllYears.RegisteredYear, CountForYear
FROM AllYears
CROSS APPLY
(
SELECT COUNT(*) AS CountForYear
FROM Student
WHERE Student.RegisteredYear = AllYears.RegisteredYear
) countForYear
只需运行此查询...
SELECT
MAX(registeredYear) as Year
,SUM(CASE WHEN gender = 'Male' THEN 1 END) AS Male
,SUM(CASE WHEN gender = 'Female' THEN 1 END) AS Female
,SUM(CASE WHEN gender IS NOT NULL THEN 1 ELSE 0 END) AS Total
FROM from student
WHERE registeredYear = 2013
GROUP BY registeredYear;
select sp.CLASS_Name , count(*) as total
, sum( case when si.STDNT_GENDER = 1 then 1 else 0 end ) as Male
, sum( case when si.STDNT_GENDER = 0 then 1 else 0 end ) as Female
from SCHOOL_PLANE sp inner join STUDENT_INFO si
on sp.CLASS_ID=si.STDNT_CLASS_PLANE_ID group by sp.CLASS_Name
-------
select sp.CLASS_Name , count(*) as total
, sum( case si.STDNT_GENDER when 1 then 1 else 0 end ) as Male
, sum( case si.STDNT_GENDER when 0 then 1 else 0 end ) as Female
from SCHOOL_PLANE sp inner join STUDENT_INFO si
on sp.CLASS_ID=si.STDNT_CLASS_PLANE_ID group by sp.CLASS_Name
------------
select sp.CLASS_Name , count(*) as total
, count( case when si.STDNT_GENDER = 1 then 1 end ) as Male
, count( case when si.STDNT_GENDER = 0 then 1 end ) as Female
from SCHOOL_PLANE sp inner join STUDENT_INFO si
on sp.CLASS_ID=si.STDNT_CLASS_PLANE_ID group by sp.CLASS_Name
Select * from (select year, count(*) as total , sum( case when gender ='M' then 1 else 0 end ) as male , sum ( case when gender ='F' then 1 else 0 end) as female from mytable where year=2013 group by gender,year)
unpivot (income_component_value forincome_component_type in (male,female,total))