不同列的骨料计数

Question

有两个表：

表一个：

id name b_id1 b_id2 b_id3 b_id4 
    1 a  10  8  null  null 
    2 b  3  4  8  10 
    3 c  10  5  4  null 

表B

b_id  title 
    3  Value3 
    4  Value4 
    5  Value 5 
    8  Value 8 
    10  Value 

表A具有FK上b_id1，b_id2 ，b_id3，b_id4到b_id cloumn上的表B，

我们打算将标题分组并计数。 类似如下的结果：

Title  Count 
Value3  1 
Value4  2 
Value5  1 
Value8  2 
Value10 3 
Null  3 

Answer 1

全部工作示例：

DECLARE @Table1 TABLE 
(
    [id] INT 
    ,[name] VARCHAR(1) 
    ,[b_id1] INT 
    ,[b_id2] INT 
    ,[b_id3] INT 
    ,[b_id4] INT 
); 

DECLARE @Table2 TABLE 
(
    [b_id] INT 
    ,[title] VARCHAR(7) 
); 

INSERT INTO @Table1 ([id], [name], [b_id1], [b_id2], [b_id3], [b_id4]) 
VALUES (1, 'a', 10, 8, NULL, NULL) 
     ,(2, 'b', 3, 4, 8, 10) 
     ,(3, 'c', 10, 5, 4, NULL); 

INSERT INTO @Table2 ([b_id], [title]) 
VALUES (3, 'Value3') 
     ,(4, 'Value4') 
     ,(5, 'Value 5') 
     ,(8, 'Value 8') 
     ,(10, 'Value'); 

SELECT T2.[title] 
     ,COUNT(*) 
FROM 
(
    SELECT [b_id1] 
    FROM @Table1 
    UNION ALL 
    SELECT [b_id2] 
    FROM @Table1 
    UNION ALL 
SELECT [b_id3] 
FROM @Table1 
UNION ALL 
SELECT [b_id4] 
FROM @Table1 
) DS 
LEFT JOIN @Table2 T2 
    ON DS.[b_id1] = T2.[b_id] 
GROUP BY T2.[title]; 

Answer 2

一种方法是象下面这样：Demo Here

;with cte 
as 
(select title,count(b_id) as val from table1 t 
join 
table2 t2 
on t.id=t2.b_id 
or 
t.b_id1=t2.b_id 
or  
t.b_id2=t2.b_id 
or  
t.b_id3=t2.b_id 
or  
t.b_id4=t2.b_id 
group by title 
) 
select * from cte 
union all 

select null,sum(case 
when b_id1 is null then 1 else 0 end)+ 
sum(case 
when b_id2 is null then 1 else 0 end) 
+sum(case 
when b_id3 is null then 1 else 0 end) 
+sum(case 
when b_id4 is null then 1 else 0 end) 

from table1 

输出：

Value 3 
Value 5 1 
Value 8 2 
Value3 2 
Value4 2 
NULL 3