sql 服务器 2008 select 行数语句

Question

我有两个table

Table_1:

id  pa_name
 1     A
 2     B
 3     C

Table_2:

id  breakfast   lunch   dinner  day day_des
1      Yes       Yes      No     1    des1
1       No        No      Yes    2    des2
1      Yes        No      Yes    3    des3
2      Yes       Yes      Yes    1    des11
2      Yes        No       No    2    des22
2       No       Yes       No    3    des33

我想要这样的结果

id  pa_name breakfast lunch dinner day_des
 1     A       2       1      2     des1
 2     B       2       2      1     des11

我正在使用 SQL Server 2008

Answer 1

将 JOIN 与 GROUP BY 合并：

select t1.id, t1.pa_name,
       SUM(case when breakfast = 'YES' then 1 end) as breakfast,
       SUM(case when lunch = 'YES' then 1 end) as lunch,
       SUM(case when dinner= 'YES' then 1 end) as dinner,
       MIN(day_des)
from Table_1 as t1 join Table_2 as t2 on t1.id = t2.id
group by t1.id, t1.pa_name

但我有点担心最近的编辑，如果有不同的值，应该如何选择 day_des？我的选择是最小值。

Answer 2

这将为您提供逗号分隔格式的值

;WITH CTE AS
(
    SELECT t1.id, t1.pa_name,
           SUM(CASE WHEN breakfast = 'YES' then 1 end) as breakfast,
           SUM(CASE WHEN lunch = 'YES' THEN 1 END) AS lunch,
           SUM(CASE WHEN dinner= 'YES' THEN 1 END) AS dinner       
    FROM Table_1 AS t1 
    JOIN Table_2 AS t2 ON t1.id = t2.id
    GROUP BY t1.id, t1.pa_name
)
SELECT *,
SUBSTRING(
        (SELECT ', ' + day_des
        FROM TABLE_2 T2 
        WHERE CTE.id=id 
        FOR XML PATH('')),2,200000) day_des
FROM CTE

SQL FIDDLE

sql 服务器 2008 select 行数语句

sql server 2008 select statement for rows count

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