Two rows in one in SQL server - sql

Question

The answer is too close, Thanks
But
The problem is that if too many records to be entered
| id | name | age | Tel
------------------------------------------
1 | 1 | Frank | 40 | null
2 | 1 | null | 50 | 7834xx
3 | 1 | Alex | null | null
4 | 1 | null | 20 | null
5 | 2 | James | null | 4121xx
Query return the Maximum value
Like:
| id | name | age | Tel
------------------------------------------
1 | 1 | Frank | 50 | 7834xx
i need Select Query like this:
| id | name | age | Tel
------------------------------------------
1 | 1 | Alex | 20 | 7834xx
what do I do? Plz?

Answer 1

Here's a roundabout way to combine the last non-empty value of 3 columns:
-- Using a table variable for test data
declare #Test table (tableId int identity(1,1), id int, name varchar(100), age int, tel varchar(30));
insert into #Test (id, name, age, tel) values
(1,'Frank',40,null),
(1,null,50,'7834xx'),
(1,'Alex',null,null),
(1,null,20,null),
(2,'James',null,'4121xx');
select n.id, n.name, a.age, t.tel
from (
select top(1) with ties id, name
from #Test
where name is not null
order by row_number() over (partition by id order by tableId desc)
) n
inner join (
select top(1) with ties id, age
from #Test
where age is not null
order by row_number() over (partition by id order by tableId desc)
) a on (n.id = a.id)
inner join (
select top(1) with ties id, tel
from #Test
where tel is not null
order by row_number() over (partition by id order by tableId desc)
) t on (n.id = t.id);
or by re-using a CTE
;with CTE AS (
select * ,
row_number() over (partition by id, iif(name is not null,1,0) order by tableId desc) as rn_name,
row_number() over (partition by id, iif(age is not null,1,0) order by tableId desc) as rn_age,
row_number() over (partition by id, iif(tel is not null,1,0) order by tableId desc) as rn_tel
from #Test
)
select n.id, n.name, a.age, t.tel
from CTE n
join CTE a on (a.id = n.id and a.age is not null and a.rn_age = 1)
join CTE t on (t.id = n.id and t.tel is not null and t.rn_tel = 1)
where (n.name is not null and n.rn_name = 1);
Result :
╔════╦══════╦═════╦════════╗
║ id ║ name ║ age ║ tel ║
╠════╬══════╬═════╬════════╣
║ 1 ║ Alex ║ 20 ║ 7834xx ║
╚════╩══════╩═════╩════════╝
After looking at this answer more than a year later.
You could also use the window function first_value for this.
Without using any join.
select Id, name, age, tel
from
(
select Id
, row_number() over (partition by id order by tableId desc) as rn
, first_value(name) over (partition by id order by iif(name is null,1,0), tableId desc) as name
, first_value(age) over (partition by id order by iif(age is null,1,0), tableId desc) as age
, first_value(tel) over (partition by id order by iif(tel is null,1,0), tableId desc) as tel
from #Test
) q
where rn = 1
and name is not null and age is not null and tel is not null;

Answer 2

One simple way is to get max as below:
Select Id, Max(name) as [Name], Max(age) as Age, Max(Tel) as Tel
from yourtable
Group by Id

Answer 3

thanks for answering and helping.
i find this query:
SELECT TOP 10
(SELECT top(1) name FROM test1 where id=1 and name is not null order by autoID desc) as name
,(SELECT top(1) age FROM test1 where id=1 and age is not null order by autoID desc) as Age
,(SELECT top(1) Tel FROM test1 where id=1 and Tel is not null order by autoID desc) as Telephon
FROM [dbo].[test1]
group by id
its worked !!!
but i thing there are another Easy Way , maybe like this:
Select Id, NotNull(name) as [Name], NotNull(age) as Age, NotNull(Tel) as Tel
from yourtable Group by Id
???