SQl按年查询结果

Question

I have a Client table with the following columns.

 Admit_date    Gender     Homeless   Unemployed    Deleted 
 4/2/2012      Male         Yes         Yes           0
 1/1/2011      Female       Yes         Yes           0
 12/2/2011     Male          No          No           0
 5/23/2009     Female       Yes         Yes           0
 4/3/2009      Male          No          No           0
 7/4/2010      Male         Yes         Yes           0
 9/2/2010      Male         Yes         Yes           0 

I need to show the percent of each group in each year. I think this will require a pivot table:

                 2009      2010     2011    2012
 Admitted         2          2        2      1
 Male            50%       100%     50%    100%
 Female          50%         0      50%      0%
 Homeless        50%       100%     50%     100%
 Unemployed      50%       100%     50%     100% 

This query gives me the count for each year:

 select year(admit_date_c) as Year_of_Admit,count((admit_date_c)) as Admitted
 from clients where deleted = '0' 
 group by year(admit_date_c)

 Year_of_Admit   Admitted
   2009             2
   2010             2
   2011             2
   2012             1

I tried numerous query iterations using Case Count but can't figure out how to get a count or percentage of Gender, Homeless and Unemployement. Once I have that, I think I can pivot the table to get the display I need.

Answer 1

I think this should do it:

select year(admit_date) as year_of_admit,
  sum(case when gender='Male' then 1 else 0 end)*100/count(*) as Male, 
  sum(case when gender='Female' then 1 else 0 end)*100/count(*) as Female, 
  sum(case when homeless='Yes' then 1 else 0 end)*100/count(*) as Homeless
from client
group by year(admit_date)

I don't know if you can have values other than Male/Female or Yes/No, like "unknown". In that case you'd have to decide whether, say, 10 males, 5 females, and 5 unknowns means 50% male, ie 50% are known to be male, or 66% males, ie 66% of those whose gender is known are male.