Merge two SELECT queries with different ORDER BY - sql

Question

I have a Story table, and I need the following query:
- first 6 rows sorted by distance (I calculate it)
- next rows are sorted by TIME property descending
declare #profileID int
set #profileID = 6
declare #longitude float
set #longitude = 17.6009169090776
declare #latitude float
set #latitude = 46.9548404806283
SELECT
first.*
FROM
(
SELECT top 6
[dbo].[Story].*,
SQRT( POWER(#Longitude - [dbo].[Story].[Longitude], 2) + POWER(#Latitude - [dbo].[Story].[Latitude], 2)) as [DistanceFromUser]
FROM
[dbo].[Follow]
LEFT JOIN
[dbo].[Story]
ON
[dbo].[Follow].[Followed] = [dbo].[Story].[ProfileID]
WHERE
[dbo].[Follow].[Follower] = #ProfileID and
[dbo].[Story].IsDraft = 0
ORDER BY
[DistanceFromUser] asc
) first
UNION ALL
SELECT
last.*
FROM
(
SELECT TOP 100 PERCENT
[dbo].[Story].*,
SQRT( POWER(#Longitude - [dbo].[Story].[Longitude], 2) + POWER(#Latitude - [dbo].[Story].[Latitude], 2)) as [DistanceFromUser]
FROM
[dbo].[Follow]
LEFT JOIN
[dbo].[Story]
ON
[dbo].[Follow].[Followed] = [dbo].[Story].[ProfileID]
WHERE
[dbo].[Follow].[Follower] = #ProfileID and
[dbo].[Story].IsDraft = 0
**ORDER BY
Time desc**
) last
My problem is the second query. It not sorts the records after the 6'th row descending by the TIME property, it sorts as ascending.
thnx

Answer 1

Try This
SELECT
first.*
FROM
(
SELECT top 6
[dbo].[Story].*,
SQRT( POWER(#Longitude - [dbo].[Story].[Longitude], 2) + POWER(#Latitude - [dbo].[Story].[Latitude], 2)) as [DistanceFromUser]
,1 as ord
FROM
[dbo].[Follow]
LEFT JOIN
[dbo].[Story]
ON
[dbo].[Follow].[Followed] = [dbo].[Story].[ProfileID]
WHERE
[dbo].[Follow].[Follower] = #ProfileID and
[dbo].[Story].IsDraft = 0
ORDER BY
[DistanceFromUser] asc
) first
UNION ALL
SELECT
last.*
FROM
(
SELECT TOP 100 PERCENT
[dbo].[Story].*,
SQRT( POWER(#Longitude - [dbo].[Story].[Longitude], 2) + POWER(#Latitude - [dbo].[Story].[Latitude], 2)) as [DistanceFromUser]
,row_number() over(order by Time desc) as ord
FROM
[dbo].[Follow]
LEFT JOIN
[dbo].[Story]
ON
[dbo].[Follow].[Followed] = [dbo].[Story].[ProfileID]
WHERE
[dbo].[Follow].[Follower] = #ProfileID and
[dbo].[Story].IsDraft = 0
**ORDER BY
Time desc**
) last
My try (example)
declare #ta as table
(
id int
,na varchar(100)
,sal numeric(18,2)
)
insert into #ta( id,na,sal) values (1,'aa',10)
insert into #ta( id,na,sal) values (3,'bb',100)
insert into #ta( id,na,sal) values (2,'c',5)
insert into #ta( id,na,sal) values (4,'dd',50)
select * from
(select top 2 * , 1 as ord from #ta order by id) as f
union all
select * from (select top 100 percent * , row_number() over(order by sal desc) ord from #ta order by sal desc
) as tt

Answer 2

If you want the result set ordered in a particular way, then the outermost SELECT needs an ORDER BY.
You can control the ordering by including multiple keys in the outer ORDER BY. If I'm reading the query correctly, the only difference is the order by, so put the logic for the queries in a CTE:
WITH sf as (
SELECT s.*,
SQRT( POWER(#Longitude - s.[Longitude], 2) + POWER(#Latitude - s.[Latitude], 2)) as [DistanceFromUser]
FROM [dbo].[Follow] f LEFT JOIN
[dbo].[Story] s
ON f.[Followed] = s.[ProfileID]
WHERE f.[Follower] = #ProfileID and
s.IsDraft = 0
)
SELECT sf.*
FROM ((SELECT TOP (6) sf.*, 1 as ord
FROM sf
ORDER BY [DistanceFromUser] ASC
) UNION ALL
(SELECT TOP (6) sf.*, 2 as ord
FROM sf
ORDER BY Time DESC
)
) sf
ORDER BY ord,
(CASE WHEN ord = 1 THEN DistanceFromUser END) ASC,
(CASE WHEN ord = 2 THEN Time END) DESC;
You can also do this with window functions:
WITH sf as (
SELECT s.*,
SQRT( POWER(#Longitude - s.[Longitude], 2) + POWER(#Latitude - s.[Latitude], 2)) as [DistanceFromUser]
FROM [dbo].[Follow] f LEFT JOIN
[dbo].[Story] s
ON f.[Followed] = s.[ProfileID]
WHERE f.[Follower] = #ProfileID and
s.IsDraft = 0
)
SELECT sf.*
FROM (SELECT sf.*,
ROW_NUMBER() OVER (ORDER BY DistanceFromUser) as seqnum_d,
ROW_NUMBER() OVER (ORDER BY Time DESC) as seqnum_t
FROM sf
)
) sf
WHERE seqnum_d <= 6 OR seqnum_t <= 6
ORDER BY ord,
(CASE WHEN seqnum_d <= 6 THEN DistanceFromUser END) ASC,
(CASE WHEN seqnum_t <= 6 THEN Time END) DESC;
Your version could include the same row twice. This version will not duplicate rows that are in the top 6 for both conditions.

Answer 3

So I ended with next solution thnx to everyone
WITH TempTable as
(
SELECT [dbo].[Story].*,
SQRT( POWER(#Longitude - [dbo].[Story].[Longitude], 2) + POWER(#Latitude - [dbo].[Story].[Latitude], 2)) as [DistanceFromUser]
FROM
[dbo].[Follow]
LEFT JOIN
[dbo].[Story]
ON [dbo].[Follow].[Followed] = [dbo].[Story].[ProfileID]
WHERE [dbo].[Follow].[Follower] = #ProfileID and
[dbo].[Story].IsDraft = 0
)
SELECT
first.*
FROM
(
SELECT top 6
*,
1 as ord
FROM
TempTable
ORDER BY
[DistanceFromUser] asc
) first
UNION ALL
SELECT
last.*
FROM
(
SELECT TOP 100 PERCENT
*,
row_number() over(order by Time desc) as ord
FROM
TempTable
ORDER BY
Time desc
) last