Запрос для генерации строки на основе значений в нескольких столбцах

Question

У меня есть таблица в базе данных, которая имеет структуру и данные следующим образом:

+-----+--------+--------+--------+--------+--------+
|  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 |
+-----+--------+--------+--------+--------+--------+

Порядок данных должен быть в порядке первого появления в столбцах, от Col1 до Col5, чтобы получить следующий вывод:

+-----+--------------------------------------------+
|  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

Я бы сделал это, используя 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;

Я не вижу преимущества перед умом в расчете структуры замечаний.

Answer 2

Это очень необычное требование, и я полагаю, что вам на самом деле не нужно указывать значения в том порядке, в котором вы запрашиваете, а отвечать на вопрос в виде вопроса:

-- 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;

Выход:

+----+------------------------------+
| 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 |
+----+------------------------------+