select top 1 record with two grouping keys - sql-server

id date value
1001 2015-06-01 A
1001 2015-06-30 B
1001 2015-07-10 C
1001 2015-07-11 D
1001 2015-08-01 E
1001 2015-08-15 F
1001 2015-08-20 G
Desired output will be
1001 2015-06-30 6 B
1001 2015-07-11 7 D
1001 2015-08-20 8 G
I would like to subset one observation only for each month for each id.
e.g. I have three records for id 1001 in July ('2015-07-01', '2015-07-10', '2015-07-20'). Therefore I just need '2015-07-20' record only. similar for other month.
SELECT
s.id,
s.value,
max(s.date) as [MaxDate],
month(s.date) as [DateMonth]
FROM
name s
WHERE
s.date between '2015-06-01' and '2015-09-01'
GROUP BY
s.id, month(s.date)
With error message
Is invalid in the select list because it is not contained in either an
aggregate function or the GROUP BY clause.
It seems there is problem when I am using the function Month()

The problem is not with the Month function. Its with the value column. Use value in GROUP BY clause too.
If you really need the value column without GROUP BY, use a CTE first get the max in the select with ID and month. Then Join on ID and MONTH with Name Table to get the value.
Something like this:
;WITH DateCTE AS
(SELECT s.id,
max(s.date) AS [MaxDate],
month(s.date) AS [DateMonth]
FROM name AS s
WHERE s.date BETWEEN '2015-06-01' AND '2015-09-01'
GROUP BY s.id, month(s.date))
SELECT s.id,
K.value,
[MaxDate],
[DateMonth]
FROM DateCTE AS S
INNER JOIN
name AS K
ON s.id = K.ID
AND [MaxDate] = K.date;
Let me know if it works

Try this:
select
res.id,
res.date,
month(res.date) as [DateMonth],
res.value
from name res
INNER JOIN
(SELECT
s.id,
max(s.date) as [MaxDate],
month(s.date) as [DateMonth]
FROM
name s
WHERE
s.date between '2015-06-01' and '2015-09-01'
GROUP BY
s.id, month(s.date)) a
ON a.id = res.id AND a.MaxDate = res.date

If your version of Sql Server supports the row_number function, you can try this:
declare #a table (
id int not null,
dt datetime not null,
val varchar(10) not null
)
insert into #a values (1001, '2015-06-01', 'A')
insert into #a values (1001, '2015-06-30', 'B')
insert into #a values (1001, '2015-07-10', 'C')
insert into #a values (1001, '2015-07-11', 'D')
insert into #a values (1001, '2015-08-01', 'E')
insert into #a values (1001, '2015-08-15', 'F')
insert into #a values (1001, '2015-08-20', 'G')
insert into #a values (1001, '2015-08-20', 'H')
insert into #a values (1002, '2015-08-20', 'I')
insert into #a values (1002, '2015-08-20', 'J')
select sub.id, sub.dt, sub.val, month(sub.dt) as [month]
from (
select id, dt, val, row_number() over (partition by id, month(dt) order by dt desc, val) as rn from #a
) as sub
where sub.rn=1

The error you are receiving because you have not added s.value in your Group by clause.

Related

Snowflake : IN operator

so I want something as below in my query
select * from table a
where a.id in(select id, max(date) from table a group by id)
I am getting error here , as IN is equivalent to = .
how to do it?
example :
id
date
1
2022-31-01
1
2022-21-03
2
2022-01-01
2
2022-02-01
I need to get only one record based on date(max). The table has more columns than just id and date
so I need to something like this in snowflake
select * from table a
where id in(select id,max(date) from table a group by id)
```-----------------------
All solutions are working , if i select from table .
but i have case statement in view where duplicate records are coming
example :
create or replace view v_test
as
select * from
(
select id,lastdatetime,*,
case when start_date < timestamp and timestamp < end
and move_date = '9999-12-31' then 'Y'
else 'N' end as IND
from table a
) a
so if any one select view where IND= 'Y', more than 1 records are coming
what i want is to select latest records for ID where IND='Y' and max(lastdatetime)
how to incorporate this logic in view?
I think you are trying to get the latest record for each id?
select *
from table a
qualify row_number() over (partition by id order by date desc) = 1
So if we look at your sub-select:
using this "data" for the examples:
with data (id, _date) as (
select column1, to_date(column2, 'yyyy-dd-mm') from values
(1, '2022-31-01'),
(1, '2022-21-03'),
(2, '2022-01-01'),
(2, '2022-02-01')
)
select id, max(_date)
from data
group by 1;
it gives:
ID
MAX(_DATE)
1
2022-03-21
2
2022-01-02
which makes it seem you want the "the last date, per id"
which can classically (ansi sql) be written:
select d.*
from data as d
join (
select
id,
max(_date) as max_date
from data
group by 1
) as c
on d.id = c.id and d._date = c.max_date
;
ID
_DATE
1
2022-03-21
2
2022-01-02
which gives you "all the rows values". BUT if you have many rows with the same last date, you will get those, in the output.
Another methods is to use a ROW_NUMBER to pick one and only one row, which is the style of answer Mike has given:
with data (id, _date, extra) as (
select column1, to_date(column2, 'yyyy-dd-mm'), column3 from values
(1, '2022-31-01', 'extra_a'),
(1, '2022-21-03', 'extra_b_double_a'),
(1, '2022-21-03', 'extra_b_double_b'),
(2, '2022-01-01', 'extra_c'),
(2, '2022-02-01', 'extra_d')
)
select *
from data
qualify row_number() over (partition by id order by _date desc) =1 ;
gives:
ID
_DATE
EXTRA
1
2022-03-21
extra_b_double_a
2
2022-01-02
extra_d
now if you want the "all rows of the last day" you method works, albeit the QUALIFY/ROW_NUMBER is faster. You can use RANK
with data (id, _date, extra) as (
select column1, to_date(column2, 'yyyy-dd-mm'), column3 from values
(1, '2022-31-01', 'extra_a'),
(1, '2022-21-03', 'extra_b_double_a'),
(1, '2022-21-03', 'extra_b_double_b'),
(2, '2022-01-01', 'extra_c'),
(2, '2022-02-01', 'extra_d')
)
select *
from data
qualify dense_rank() over (partition by id order by _date desc) =1 ;
ID
_DATE
EXTRA
1
2022-03-21
extra_b_double_a
1
2022-03-21
extra_b_double_b
2
2022-01-02
extra_d
Now the last thing that it almost seems you are asking for, is "how do find the ID with the most recent data (here 1) and get all rows for that"
with data (id, _date, extra) as (
select column1, to_date(column2, 'yyyy-dd-mm'), column3 from values
(1, '2022-31-01', 'extra_a'),
(1, '2022-21-03', 'extra_b_double_a'),
(1, '2022-21-03', 'extra_b_double_b'),
(2, '2022-01-01', 'extra_c'),
(2, '2022-02-01', 'extra_d')
)
select *
from data
qualify id = last_value(id) over (order by _date);
Here is an example of how to use the in operator with a subquery:
select * from table1 t1 where t1.id in (select t2.id from table2 t2);
Usage of IN is possible to match on both columns:
select *
from tab AS a
where (a.id, a.date) in (select id, max(date) from tab group by id);
For sample data:
CREATE TABLE tab (id, date)
AS
SELECT column1, to_date(column2, 'yyyy-dd-mm')
FROM VALUES
(1, '2022-31-01'),
(1, '2022-21-03'),
(2, '2022-01-01'),
(2, '2022-02-01');
Output:

What is the most effcient way to replace values in a specific column of a table for this specific scenario?

I am using SQL Server 2014 and I have a table in my database called t1 (extract of only 2 columns shown below):
ResaID StayDate
100 2020-02-03
100 2020-02-04
100 2020-02-05
120 2020-04-06
120 2020-04-07
120 2020-04-08
120 2020-04-09
120 2020-04-10
I need to change the dates in the StayDate column based on the following information (extract shown exactly as provided):
ID StartDate EndDate
100 2020-06-04 2020-06-06
120 2021-03-01 2021-03-05
I have started writing my T-SQL query as follows (but it is getting quite tedious as I have to do it for more than 100 ResaID!):
USE MyDatabase
UPDATE t1
SET StayDate = CASE WHEN ResaID = 100 and StayDate = '2020-02-03' THEN '2020-06-04'
WHEN ResaID = 100 and StayDate = '2020-02-04' THEN '2020-06-05'
WHEN ResaID = 100 and StayDate = '2020-02-05' THEN '2020-06-06'
...
ELSE StayDate
END
Is there a more efficient way to tackle this problem?
You can use recursive approach :
with r_cte as (
select id, convert(date, startdate) as startdate, convert(date, enddate) as enddate
from ( values (100, '2020-06-04', '2020-06-06'),
(120, '2021-03-01', '2021-03-03')
) t(id, startdate, enddate)
union all
select id, dateadd(day, 1, startdate), enddate
from cte c
where startdate < enddate
), r_cte_seq as (
select r.cte.*, row_number() over(partition by id order by startdate) as seq
from r_cte
), cte_seq as (
select t1.*, row_number() over (partition by ResaID order by staydate) as seq
from t1
)
update cs
set cs.staydate = rc.startdate
from cte_seq cs inner join
r_cte_seq rc
on rc.id = cs.ResaID and rc.seq = cs.seq;
Here is my approach to this problem. I would use a numbers table to generate a record for each date in the new range for each reservation ID. I would then partition this data by reservation ID, ordered by the date. Doing the same partition logic on the existing data will allow records to be properly joined together.
I would then do a DELETE operation followed by an INSERT operation. This would leave you with the appropriate amount of records. The only manual thing that would need to be done is to populate the auxiliary data for reservations with expanded date ranges. I expanded one of your new ranges to show this scenario.
I've marked where the setup for this demo ends in the code below. Everything below that is my intended solution that should be able to be implemented with your real tables.
--Ranges Table
DECLARE #ranges TABLE
(
ID INT
,StartDate DATETIME
,EndDate DATETIME
)
DECLARE #t1 TABLE
(
ResaID INT
,StayDate DATETIME
,ColA INT
,ColB NVARCHAR(100)
,ColC BIT
)
INSERT INTO #t1
(
ResaID
,StayDate
,ColA
,ColB
,ColC
)
VALUES
(100, '2020-02-03', 1, 'A', 0)
,(100, '2020-02-04', 100, 'B', 1)
,(100, '2020-02-05', 255, 'C', 1)
,(120, '2020-04-06', 34, 'D', 1)
,(120, '2020-04-07', 67, 'E', 0)
,(120, '2020-04-08', 87, 'F', 0)
,(120, '2020-04-09', 545, 'G', 1)
,(120, '2020-04-10', 288, 'H', 0)
INSERT INTO #ranges
(
ID
,StartDate
,EndDate
)
VALUES
(100, '2020-06-04', '2020-06-07')
,(120, '2021-03-01', '2021-03-05')
--END DEMO SETUP
DROP TABLE IF EXISTS #numbers
DROP TABLE IF EXISTS #newRecords
--GENERATE NUMBERS TABLE
;WITH e1(n) AS
(
SELECT 1 UNION ALL SELECT 1 UNION ALL SELECT 1 UNION ALL
SELECT 1 UNION ALL SELECT 1 UNION ALL SELECT 1 UNION ALL
SELECT 1 UNION ALL SELECT 1 UNION ALL SELECT 1 UNION ALL SELECT 1
), -- 10
e2(n) AS (SELECT 1 FROM e1 CROSS JOIN e1 AS b), -- 10*10
e3(n) AS (SELECT 1 FROM e2 CROSS JOIN e2 AS b), -- 100*100
e4(n) AS (SELECT 1 FROM e3 CROSS JOIN (SELECT TOP 5 n FROM e1) AS b) -- 5*10000
SELECT ROW_NUMBER() OVER (ORDER BY n) as Num
INTO #numbers
FROM e4
ORDER BY n;
;with oldData --PARTITION THE EXISTING RECORDS
AS
(
SELECT *
,ROW_NUMBER() OVER (PARTITION BY ResaID ORDER BY STAYDATE) as ResPartID
FROM #t1
)
,newRanges --GENERATE YOUR NEW RANGES AND PARITITION
AS
(
select
r.ID
,CAST(n.num as DATETIME) as StayDate
,ROW_NUMBER() OVER (PARTITION BY ID ORDER BY n.num) as ResPartID
from #ranges r
inner join #numbers n on CAST(r.StartDate as INT) <= n.Num AND CAST(r.EndDate as INT) >= n.Num
)
SELECT n.ID
,n.StayDate
,o.ColA
,o.ColB
,o.ColC
into #newRecords
FROM newRanges n
left join oldData o on n.ID = o.ResaID and n.ResPartID = o.ResPartID
--DELETE OLD RECORDS
DELETE t
FROM #t1 t
inner join #ranges r on t.ResaID = r.ID
--INSERT NEW DATA
INSERT INTO #t1
(
ResaID
,StayDate
,ColA
,ColB
,ColC
)
SELECT
ID
,StayDate
,ColA
,ColB
,ColC
FROM #newRecords
SELECT * FROM #t1
The following code converts the t1 dates into ranges and then uses the corresponding range dates to calculate new StayDate values. You can swap out the final select for one of the commented statements to see what is going on in the CTEs. The final select can be replaced with an update if you want to change the original table data.
-- Thanks to Aaron Hughes for setting up the sample data.
-- I changed the DateTime columns to Date .
--Ranges Table
DECLARE #ranges TABLE
(
ID INT
,StartDate DATE
,EndDate DATE
)
DECLARE #t1 TABLE
(
ResaID INT
,StayDate DATE
,ColA INT
,ColB NVARCHAR(100)
,ColC BIT
)
INSERT INTO #t1
(
ResaID
,StayDate
,ColA
,ColB
,ColC
)
VALUES
(100, '2020-02-03', 1, 'A', 0)
,(100, '2020-02-04', 100, 'B', 1)
,(100, '2020-02-05', 255, 'C', 1)
,(120, '2020-04-06', 34, 'D', 1)
,(120, '2020-04-07', 67, 'E', 0)
,(120, '2020-04-08', 87, 'F', 0)
,(120, '2020-04-09', 545, 'G', 1)
,(120, '2020-04-10', 288, 'H', 0)
INSERT INTO #ranges
(
ID
,StartDate
,EndDate
)
VALUES
(100, '2020-06-04', '2020-06-07')
,(120, '2021-03-01', '2021-03-05');
with
-- Calculate the date range for each stay in #t1 .
ResaRanges as (
select ResaId, Min( StayDate ) as ResaStartDate, Max( StayDate ) as ResaEndDate
from #t1
group by ResaId ),
-- Match up the #t1 date ranges with the #ranges date ranges.
CombinedRanges as (
select RR.ResaId, RR.ResaStartDate, RR.ResaEndDate, DateDiff( day, RR.ResaStartDate, RR.ResaEndDate ) + 1 as ResaDays,
R.StartDate, R.EndDate, DateDiff( day, R.StartDate, R.EndDate ) + 1 as RangeDays,
DateDiff( day, RR.ResaStartDate, R.StartDate ) as DaysOffset
from ResaRanges as RR inner join
#ranges as R on R.ID = RR.ResaId )
-- Calculate the new StayDate values for all #t1 ranges that are not longer than the corresponding #range .
-- The difference between range starting dates is added to each StayDate .
select T.ResaId, T.StayDate, DateAdd( day, CR.DaysOffset, T.StayDate ) as NewStayDate
from #t1 as T inner join
CombinedRanges as CR on CR.ResaID = T.ResaID
where CR.RangeDays >= CR.ResaDays;
-- To see the steps you can use one of the following select staements to view the intermediate results:
-- select * from ResaRanges;
-- select * from CombinedRanges;

SQL Server: max of date

Table 1
RefId Name
----- ----
1 A
2 B
Table 2
RefId Date
----- -----
1 29/03/2018 07:15
1 29/03/2018 07:30
2 29/03/2018 07:35
2 29/03/2018 07:40
I would like the result to be as follows (Refid name and the max(date) from table 1 and 2 for that refid)
1 A 29/03/2018 07:30
2 B 29/03/2018 07:40
Query used
select
table1.refId, table1.name,
(select max(date) from table2)
from
table1, table2
where
table1.refid = table2.refid
group by
table2.refid
I am getting the following error message
Column is invalid in the select list because it is not contained in either an aggregate function or the GROUP BY clause.
Use JOIN and the aggregate function MAX with GROUP BY to select the max date for each RefId.
Query
select [t1].[RefId], [t1].[Name], max([t2].[date] as [date]
from [Table1] [t1]
join [Table2] [t2]
on [t1].[RefId] = [t2].[RefId]
group by [t1].[RefId], [t1].[Name];
'29/03/2018 07:15' is nvarchar-type, you need datetime.
nvarchar convert to datetime: SELECT CONVERT(datetime, '29/03/2018 07:15', 103)
Answer to your example:
DECLARE #Table1 TABLE(RefId int, Name nvarchar(10));
INSERT INTO #Table1(RefId, Name) VALUES(1, 'A'), (2, 'B');
DECLARE #Table2 TABLE(RefId int, [Date] nvarchar(50));
INSERT INTO #Table2(RefId, [Date])
VALUES
(1, '29/03/2018 07:15'),
(1, '29/03/2018 07:30'),
(2, '29/03/2018 07:35'),
(2, '29/03/2018 07:40');
SELECT t1.RefId, t1.Name, t2.Date
FROM #Table1 AS t1
INNER JOIN
(SELECT RefId, MAX(CONVERT(datetime, [Date], 103)) AS [Date]
FROM #Table2
GROUP BY RefId) AS t2
ON t1.RefId = t2.RefId

SQL - Filter on dates X number of days apart from the previous

I have a table containing orders. I would like to select those orders that are a certain number of days apart for a specific client. For example, in the table below I would like to select all of the orders for CustomerID = 10 that are at least 30 days apart from the previous instance. With the starting point to be the first occurrence (07/05/2014 in this data).
OrderID | CustomerID | OrderDate
==========================================
1 10 07/05/2014
2 10 07/15/2014
3 11 07/20/2014
4 11 08/20/2014
5 11 09/21/2014
6 10 09/23/2014
7 10 10/15/2014
8 10 10/30/2014
I would want to select OrderIDs (1,6,8) since they are 30 days apart from each other and all from CustomerID = 10. OrderIDs 2 and 7 would not be included as they are within 30 days of the previous order for that customer.
What confuses me is how to set the "checkpoint" to the last valid date. Here is a little "pseudo" SQL.
SELECT OrderID
FROM Orders
WHERE CusomerID = 10
AND OrderDate > LastValidOrderDate + 30
i came here and i saw #SveinFidjestøl already posted answer but i can't control my self after by long tried :
with the help of LAG and LEAD we can comparison between same column
and as per your Q you are looking 1,6,8. might be this is helpful
SQL SERVER 2012 and after
declare #temp table
(orderid int,
customerid int,
orderDate date
);
insert into #temp values (1, 10, '07/05/2014')
insert into #temp values (2, 10, '07/15/2014')
insert into #temp values (3, 11, '07/20/2014')
insert into #temp values (4, 11, '08/20/2014')
insert into #temp values (5, 11, '09/21/2014')
insert into #temp values (6, 10, '09/23/2014')
insert into #temp values (7, 10, '10/15/2014')
insert into #temp values (8, 10, '10/30/2014');
with cte as
(SELECT orderid,customerid,orderDate,
LAG(orderDate) OVER (ORDER BY orderid ) PreviousValue,
LEAD(orderDate) OVER (ORDER BY orderid) NextValue,
rownum = ROW_NUMBER() OVER (ORDER BY orderid)
FROM #temp
WHERE customerid = 10)
select orderid,customerid,orderDate from cte
where DATEDIFF ( day , PreviousValue , orderDate) > 30
or PreviousValue is null or NextValue is null
SQL SERVER 2005 and after
WITH CTE AS (
SELECT
rownum = ROW_NUMBER() OVER (ORDER BY p.orderid),
p.orderid,
p.customerid,
p.orderDate
FROM #temp p
where p.customerid = 10)
SELECT CTE.orderid,CTE.customerid,CTE.orderDate,
prev.orderDate PreviousValue,
nex.orderDate NextValue
FROM CTE
LEFT JOIN CTE prev ON prev.rownum = CTE.rownum - 1
LEFT JOIN CTE nex ON nex.rownum = CTE.rownum + 1
where CTE.customerid = 10
and
DATEDIFF ( day , prev.orderDate , CTE.orderDate) > 30
or prev.orderDate is null or nex.orderDate is null
GO
You can use the LAG() function, available in SQL Server 2012, together with a Common Table Expression. You calculate the days between the customer's current order and the customer's previous order and then query the Common Table Expression using the filter >= 30
with cte as
(select OrderId
,CustomerId
,datediff(d
,lag(orderdate) over (partition by CustomerId order by OrderDate)
,OrderDate) DaysSinceLastOrder
from Orders)
select OrderId, CustomerId, DaysSinceLastOrder
from cte
where DaysSinceLastOrder >= 30 or DaysSinceLastOrder is null
Results:
OrderId CustomerId DaysSinceLastOrder
1 10 NULL
6 10 70
3 11 NULL
4 11 31
5 11 32
(Note that 1970-01-01 is chosen arbitrarily, you may choose any date)
Update
A slighty more reliable way of doing it will involve a temporary table. But the original table tbl can be left unchanged. See here:
CREATE TABLE #tmp (id int); -- set-up temp table
INSERT INTO #tmp VALUES (1); -- plant "seed": first oid
WHILE (##ROWCOUNT>0)
INSERT INTO #tmp (id)
SELECT TOP 1 OrderId FROM tbl
WHERE OrderId>0 AND CustomerId=10
AND OrderDate>(SELECT max(OrderDate)+30 FROM tbl INNER JOIN #tmp ON id=OrderId)
ORDER BY OrderDate;
-- now list all found entries of tbl:
SELECT * FROM tbl WHERE EXISTS (SELECT 1 FROM #tmp WHERE id=OrderId)
#tinka shows how to use CTEs to do the trick, and the new windowed functions (for 2012 and later) are probably the best answer. There is also the option, assuming you do not have a very large data set, to use a recursive CTE.
Example:
declare #customerid int = 10;
declare #temp table
(orderid int,
customerid int,
orderDate date
);
insert into #temp values (1, 10, '07/05/2014')
insert into #temp values (2, 10, '07/15/2014')
insert into #temp values (3, 11, '07/20/2014')
insert into #temp values (4, 11, '08/20/2014')
insert into #temp values (5, 11, '09/21/2014')
insert into #temp values (6, 10, '09/23/2014')
insert into #temp values (7, 10, '10/15/2014')
insert into #temp values (8, 10, '10/30/2014');
with datefilter AS
(
SELECT row_number() OVER(PARTITION BY CustomerId ORDER BY OrderDate) as RowId,
OrderId,
CustomerId,
OrderDate,
DATEADD(day, 30, OrderDate) as FilterDate
from #temp
WHERE CustomerId = #customerid
)
, firstdate as
(
SELECT RowId, OrderId, CustomerId, OrderDate, FilterDate
FROM datefilter
WHERE rowId = 1
union all
SELECT datefilter.RowId, datefilter.OrderId, datefilter.CustomerId,
datefilter.OrderDate, datefilter.FilterDate
FROM datefilter
join firstdate
on datefilter.CustomerId = firstdate.CustomerId
and datefilter.OrderDate > firstdate.FilterDate
WHERE NOT EXISTS
(
SELECT 1 FROM datefilter betweens
WHERE betweens.CustomerId = firstdate.CustomerId
AND betweens.orderdate > firstdate.FilterDate
AND datefilter.orderdate > betweens.orderdate
)
)
SELECT * FROM firstdate

Convert rows to columns

I have the follwoing structure:
Emp PayDate Amount
1 11/23/2010 500
1 11/25/2010 -900
1 11/28/2010 1000
1 11/29/2010 2000
2 11/25/2010 2000
3 11/28/2010 -3000
2 11/28/2010 4000
3 11/29/2010 -5000
I need to get the following result if emp 1 is selected (top 3 dates and their corresponding vals - if they exist - 4th row is always ignored)
PayDate1 Amount1 Paydate2 Amount2 Paydate3 Amount3
11/23/2010 500 11/25/2010 -900 11/28/2010 1000
I need to get the following result if emp 2 is selected
Paydate1 Amount1 Paydate2 Amount2 Paydate3 Amount3
11/25/2010 2000 11/28/2010 4000 NULL NULL
I need to get the following result if emp 3 is selected
Paydate1 Amount1 Paydate2 Amount2 Paydate3 Amount3
11/28/2010 -3000 11/29/2010 -5000
To get the respective data in rows I can run the following query:
select top 3 Paydate, Amount from Table where Emp = #Emp
But how do I get result in a pivoted fashion?
There's an excellent article on Pivots with SQL Server 2005+ here.
CREATE TABLE dbo.Table1
(
Emp int,
PayDate datetime,
Amount int
)
GO
INSERT INTO dbo.Table1 VALUES (1, '11/23/2010',500)
INSERT INTO dbo.Table1 VALUES (1, '11/25/2010',-900)
INSERT INTO dbo.Table1 VALUES (1, '11/28/2010',1000)
INSERT INTO dbo.Table1 VALUES (1, '11/29/2010',2000)
INSERT INTO dbo.Table1 VALUES (2, '11/25/2010',2000)
INSERT INTO dbo.Table1 VALUES (3, '11/28/2010',-3000)
INSERT INTO dbo.Table1 VALUES (2, '11/28/2010',4000)
INSERT INTO dbo.Table1 VALUES (3, '11/29/2010',-5000)
;WITH cte AS
(SELECT Emp, PayDate, Amount, PayDateRowNumber
FROM
(SELECT Emp,
PayDate,
Amount,
ROW_NUMBER() OVER (PARTITION BY Emp ORDER BY PayDate) AS PayDateRowNumber
FROM Table1) AS RankedTable1
WHERE PayDateRowNumber < 4)
SELECT c1.Emp AS Emp, c1.PayDate AS PayDate1
,c1.Amount AS Amount1, c2.PayDate AS PayDate2
,c2.Amount AS Amount2, c3.PayDate AS PayDate3, c3.Amount AS Amount3
FROM cte c1
LEFT JOIN cte c2 ON c2.Emp = c1.Emp AND c2.PayDateRowNumber = 2
LEFT JOIN cte c3 ON c3.Emp = c2.Emp AND c3.PayDateRowNumber = 3
WHERE c1.PayDateRowNumber = 1
Output is:
Some caveats are that it won't aggregate amounts for the same employer/date (though can easily be changed). Also may want to change to review use of ROW_NUMBER() versus RANK() and DENSE_RANK() depending on your definition of "TOP 3"

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