Question

我在数据库中有一个表，其结构和数据如下：

+-----+--------+--------+--------+--------+--------+
|  ID |  Col1  |  Col2  |  Col3  |  Col4  |  Col5  |
+-----+--------+--------+--------+--------+--------+
|  1  |  MALE  |  MALE  | FEMALE |  NULL  |  NULL  |
|  2  | FEMALE |  MALE  |  NULL  |  NULL  |  NULL  |
|  3  | FEMALE |  NULL  |  NULL  |  NULL  |  NULL  |
|  4  |  MALE  | OTHER  | FEMALE | FEMALE |  NULL  |
|  5  |  MALE  | OTHER  | FEMALE |  MALE  | FEMALE |
+-----+--------+--------+--------+--------+--------+

数据的顺序必须按列中的第一次出现顺序排列，从Col1到Col5，以获得以下输出：

+-----+--------------------------------------------+
|  ID | Remarks                                    |
+-----+--------------------------------------------+
|  1  | 2 Male and 1 Female                        |
|  2  | 1 Female and 1 Male                        |
|  3  | 1 Female                                   |
|  4  | 1 Male, 1 Other and 2 Female               |
|  5  | 2 Male, 1 Other and 2 Female               |
+-----+--------------------------------------------+

Answer 1

我会这样做apply。

select t.*,
       (case when num_male = 0 and num_female = 0 and num_other = 0
             then ''
             when num_male = 0 and num_female = 0
             then replace('num_other OTHER', 'num_other', num_other)
             when num_male = 0 and num_other = 0
             then replace('num_female FEMALE', 'num_female', num_female)
             when num_male = 0 and num_female = 0
             then replace('num_male MALE', 'num_male', num_male)
             when num_male = 0 
             then replace(replace(replace('num_other OTHER AND num_female FEMALE'), 'num_male', num_male), 'num_other', num_other), 'num_female', num_female)
             when num_other = 0 
             then replace(replace(replace('num_male MALE AND num_female FEMALE), 'num_male', num_male), 'num_other', num_other), 'num_female', num_female)
             when num_female = 0 
             then replace(replace(replace('num_male MALE AND num_other OTHER), 'num_male', num_male), 'num_other', num_other), 'num_female', num_female)
             else replace(replace(replace('num_male MALE, num_other OTHER AND num_female FEMALE), 'num_male', num_male), 'num_other', num_other), 'num_female', num_female)
        end) as remarks
from t cross apply
     (select sum(case when col = 'FEMALE' then 1 else 0 end) as num_females,
             sum(case when col = 'MALE' then 1 else 0 end) as num_males,
             sum(case when col = 'OTHER' then 1 else 0 end) as num_other
      from (values (col1), (col2), (col3), (col4), (col5)) v(col)
     ) v;

在计算评论结构时，我没有看到聪明的优势。

Answer 2

这是一个非常不寻常的要求，我想你不会真的需要按照你要求的顺序获取值，而是回答问题：

-- Build data
declare @t table(ID int,Col1 varchar(10),Col2 varchar(10),Col3 varchar(10),Col4 varchar(10),Col5 varchar(10));
insert into @t values
 (1,'MALE','MALE','FEMALE',null,null)
,(2,'FEMALE','MALE',null,null,null)
,(3,'FEMALE',null,null,null,null)
,(4,'MALE','OTHER','FEMALE','FEMALE',null)
,(5,'MALE','OTHER','FEMALE','MALE','FEMALE')
;

-- Query
with d as
(   -- Manually unpivot the 5 Cols and add a row number
    select 1 as r
            ,ID
            ,Col1 as Col
    from @t
    union all
    select 2
            ,ID
            ,Col2 as Col
    from @t
    union all
    select 3
            ,ID
            ,Col3 as Col
    from @t
    union all
    select 4
            ,ID
            ,Col4 as Col
    from @t
    union all
    select 5
            ,ID
            ,Col5 as Col
    from @t
)
,c as
(   -- Replace Col values for presentation and add in aggregated row numbers, ranks and counts for each value
    select ID
            ,case Col when 'MALE' then 'Male'
                        when 'FEMALE' then 'Female'
                        when 'OTHER' then 'Other'
                        end as Col
            ,row_number() over (partition by ID order by r) as rn
            ,dense_rank() over (partition by ID order by r) as drk
            ,rank() over (partition by ID, Col order by r) as rk
            ,count(Col) over (partition by ID, Col) as c
    from d
    where Col is not null
)
,o as
(   -- Filter rows down to just the first instance of that Col value to get the presentation order
    select ID
            ,row_number() over (partition by ID order by rn) as o
            ,cast(c as varchar(10)) + ' ' + Col as c
    from c
    where rk = 1
)
    -- Collate the data per presentation rules
select o.ID
        ,o.c
         + isnull(case when o3.ID is null
                    then ' and ' + o2.c
                    else ', ' + o2.c + ' and ' + o3.c
                    end
                    ,'') as Remarks
from o
    left join o as o2
        on o.ID = o2.ID
            and o2.o = 2
    left join o as o3
        on o.ID = o3.ID
            and o3.o = 3
where o.o = 1
order by o.ID;

输出：

+----+------------------------------+
| ID |           Remarks            |
+----+------------------------------+
|  1 | 2 Male and 1 Female          |
|  2 | 1 Female and 1 Male          |
|  3 | 1 Female                     |
|  4 | 1 Male, 1 Other and 2 Female |
|  5 | 2 Male, 1 Other and 2 Female |
+----+------------------------------+

查询以基于多列中的值生成字符串

2 个答案: