Select alternate rows from SQL Server table - sql-server

Question

I am working with SQL Server 2008. I have a table which does not contain any unique columns; how to get alternate rows from it?
SQL Server table:
+-----+--------+
| id | name |
|-----+--------|
| 1 | abc |
| 2 | pqr |
| 2 | pqr |
| 3 | xyz |
| 4 | lmn |
| 5 | efg |
| 5 | efg |
+-----+--------+
As we've to come with at least one working suggestion with the question, I've tried below code; which is not so proper technique when fetching from a huge amount of data.
Trial:
create table #tmp
(
id int, name varchar(10), srNo int
)
insert into #tmp
select
id, name,
ROW_NUMBER() OVER (ORDER BY id) % 2 as srNo --,alternate rows
from
Employee
select *
from #tmp
where srNo = 1 --or srNo = 0
Above query gives out alternate rows i.e. 1st, 3rd, 5th OR 2nd, 4th, 6th etc.
Please help me out with proper way without #tmp to achieve the goal!

Answer 1

You can just use your select statement as an in-line view. You don't need the #tmp table.
select t.id, name
from (select id, name, ROW_NUMBER() over (order by id) as srNo from Employee) t
where (t.srNo % 2) = 1
SqlFiddle

Answer 2

--To fetch ALTERNATE records from a table (EVEN NUMBERED)
Select * from TableName where ColumnName % 2 = 0
For Eg : select * from HumanResources.Employee where BusinessEntityID % 2 = 0
--To fetch ALTERNATE records from a table (ODD NUMBERED)
Select * from TableName where ColumnName % 2 = 1
For Eg : select * from HumanResources.Employee where BusinessEntityID % 2 = 1

Answer 3

I'm taking student as a table name.
Here is my answer ->
For Even Row Number -
> SELECT id from (SELECT rowno, id from student) where mod(rowno,2)=0
For Odd Row Number -
> SELECT id from (SELECT rowno, id from student) where mod(rowno,2)=1

Answer 4

Same also can be achieved using having clause; but it adds group by task:
SELECT id, name
FROM (SELECT id, name, ROW_NUMBER()over(order by id) AS srNo FROM Employee) x
GROUP BY srNo, id, name
HAVING (srNo % 2) = 0

Answer 5

You can just use your select statement as an in-line view. You don't need the #tblCities table.
select tbl1.CityID,tbl1.CityName from (select ROW_NUMBER() over(order by CityID asc) as row_no,CityID,CityName from tblCities) as tbl1 where tbl1.row_no%2=1

Answer 6

declare #t table
(
id int,
name nvarchar(20)
)
insert into #t
Select 1, 'abc'
union all
Select 2, 'pqr'
union all
Select 2, 'pqr'
union all
Select 3, 'xyz'
union all
Select 4, 'lmn'
union all
Select 5, 'efg'
union all
Select 2, 'efg'
Select * from(
Select *, row_number() over(order by id) as rnum from #t ) t where rnum % 2 <> 0

Answer 7

create table t (id bigint NOT NULL, input_1 boolean not null, data_gps timestamp(0) not null);
insert into t (id, input_1,data_gps) values
(1, false , '2022-01-01 15:42:07'),
(2, true , '2022-01-02 15:42:07'),
(3, true , '2022-01-03 15:42:07'),
(4, false , '2022-01-04 15:42:07'),
(5, true , '2022-01-05 15:42:07'),
(6, true , '2022-01-06 15:42:07'),
(7, true , '2022-01-07 15:42:07'),
(8, true , '2022-01-08 15:42:07'),
(9, false , '2022-01-09 15:42:07'),
(10 ,true , '2022-01-10 15:42:07'),
(11, true , '2022-01-11 15:42:07'),
(12, true , '2022-01-12 15:42:07'),
(13, false , '2022-01-13 15:42:07'),
(14, true , '2022-01-14 15:42:07');
you will have
Here is the query that will group by value change
select input_1, min(data_gps) as mind, max(data_gps) as maxd
from (
select input_1, data_gps,
row_number() over (order by data_gps)
- row_number() over (partition by input_1 order by data_gps) as grp
from t
) as tmp
group by input_1, grp
order by min(data_gps);
The results
DEMO
https://dbfiddle.uk/6Ajy3H5O