Question

我已经使用SQL几个月了，我在为这项特定任务确定一些事情时遇到了麻烦：

SQL能否以我需要的方式输出数据？
如果是这样，我应该使用哪种方法来实现？

我所拥有的表格按照年级分列了每所学校，第二栏有每个年级的总入学率。我正在努力为所有学校的所有入学学生提供以下所需产出的总和：

Grade Total Enrolled
K       7,871
1       8,321
2       8,087
3       8,164
4       8,237
5       8,055

感谢您的帮助！

我使用子查询尝试了这一点，但它显示了表格中所有记录的每一行重复的总数，而不是一行总计。

子查询：

SELECT (SELECT SUM(Totalenrollment) FROM Dbo.['2013Cycle_1_Data']
  WHERE Grade LIKE '%6%'    AND Level = 'MS' ) AS Grade6

CTE代码：

WITH 
  TK AS (  SELECT SUM(Totalenrollment) AS Kindergarten FROM Dbo.['2013Cycle_1_Data'] WHERE Grade LIKE '%KIND%' AND Level = 'ES' )
, T1 AS (  SELECT SUM(Totalenrollment) AS Grade1       FROM Dbo.['2013Cycle_1_Data'] WHERE Grade LIKE '%1%'    AND Level = 'ES' )
, T2 AS (  SELECT SUM(Totalenrollment) AS Grade2       FROM Dbo.['2013Cycle_1_Data'] WHERE Grade LIKE '%2%'    AND Level = 'ES' )
, T3 AS (  SELECT SUM(Totalenrollment) AS Grade3       FROM Dbo.['2013Cycle_1_Data'] WHERE Grade LIKE '%3%'    AND Level = 'ES' )
, T4 AS (  SELECT SUM(Totalenrollment) AS Grade4       FROM Dbo.['2013Cycle_1_Data'] WHERE Grade LIKE '%4%'    AND Level = 'ES' )
, T5 AS (  SELECT SUM(Totalenrollment) AS Grade5       FROM Dbo.['2013Cycle_1_Data'] WHERE Grade LIKE '%5%'    AND Level = 'ES' )   

SELECT * FROM TK 
UNION ALL
SELECT * FROM T1 
UNION ALL
SELECT * FROM T2 
UNION ALL 
SELECT * FROM T3
UNION ALL
SELECT * FROM T4 
UNION ALL
SELECT * FROM T5

Answer 1

只需使用CASE语句确定成绩水平，然后按年级分组：

select 
    case 
        when Grade LIKE '%KIND%' AND Level = 'ES' then 'K'
        when Grade LIKE '%1%'    AND Level = 'ES'  then '1'
        else 'Other Grades' 
    end as GradeLevel,
    sum(TotalEnrollment) as Enrolled
from
    Dbo.['2013Cycle_1_Data']
 group by
    case 
      when Grade LIKE '%KIND%' AND Level = 'ES' then 'K'
      when Grade LIKE '%1%'    AND Level = 'ES'  then '1'
      else 'Other Grades'   
    end

我应该使用CTE，子查询，临时表还是其他方法？

1 个答案: