imex (11/4/2012)
Hi,Try:
selecta.SNo,
a.Date,
a.Cat as Cat_A,
a.Value as Value_A,
b.Cat as Cat_B,
b.Value as Value_B,
c.Cat as Cat_C,
c.Value as Value_C
from MyTable as a
left join MyTable as b
on b.Date = a.Date and b.Cat = 'B'
left join MyTable as c
on c.Date = c.Date and c.Cat = 'C'
where a.Cat = 'A'
Hope this helps.
A double self-join? :w00t:
How about a single table scan instead:
DECLARE @T TABLE
(SNo INT, Date DATETIME, CAT CHAR(1), Value INT)
INSERT INTO @T (SNo, Date, Cat, Value)
SELECT 1, '2011-11-01','A',100
UNION ALL SELECT 2, '2011-11-02','A',101
UNION ALL SELECT 3, '2011-11-01','B',102
UNION ALL SELECT 4, '2011-11-02','B',100
UNION ALL SELECT 5, '2011-11-01','C',1088
UNION ALL SELECT 5, '2011-11-02','C',1026
SELECT SNo=ROW_NUMBER() OVER (ORDER BY Date)
,Date, Cat_A, Value_A, Cat_B, Value_B, Cat_C, Value_C
FROM (
SELECT Date
,Cat_A='A'
,Value_A=MAX(CASE Cat WHEN 'A' THEN Value END)
,Cat_B='B'
,Value_B=MAX(CASE Cat WHEN 'B' THEN Value END)
,Cat_C='C'
,Value_C=MAX(CASE Cat WHEN 'C' THEN Value END)
FROM @T
GROUP BY Date) a
My thought question: Have you ever been told that your query runs too fast?
My advice:
INDEXing a poor-performing query is like putting sugar on cat food. Yeah, it probably tastes better but are you sure you want to eat it?
The path of least resistance can be a slippery slope. Take care that fixing your fixes of fixes doesn't snowball and end up costing you more than fixing the root cause would have in the first place.
Need to UNPIVOT? Why not CROSS APPLY VALUES instead?[/url]
Since random numbers are too important to be left to chance, let's generate some![/url]
Learn to understand recursive CTEs by example.[/url]
[url url=http://www.sqlservercentral.com/articles/St