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SQL Select Max Date and Previous Date?

Posted on 2014-01-29
8
2,124 Views
Last Modified: 2014-02-04
I'm having trouble selecting the Max date and Previous date. I tried the following code and it just changes the date, the price column data remains the same.

[Max Date w/ Price]
select Price, Max(date)
 from table1
 where Code = 4235
 group by Price

--- Result ---
Price              EffDate
1234.0000      2012-07-28 00:00:00.000
1255.0000      2012-07-30 00:00:00.000

[Previous Date w/ Price]
select Price, Max(date) -1
 from table1
 where Code = 4235
 group by Price

--- Result ---
Price              EffDate
1234.0000      2012-07-27 00:00:00.000
1255.0000      2012-07-29 00:00:00.000

[Previous Date w/ Price]
select Price, Max(date) -1
 from table1
 where Code = 4235
 group by Price

Then I tried moving the Max Date into the Where Clause like so, but it needs a Having clause:

[Previous Date w/ Price]
select Price, Date
 from table1
 where Code = 4235
and Date = Max(Date) -1
 group by Price

Help...
0
Comment
Question by:WorknHardr
8 Comments
 
LVL 15

Expert Comment

by:gplana
ID: 39818449
you can't put agregate functions (like max, min, sum, count, avg) on a where clause. A where clause filters original rows from the table.

What you need is to use a having clause to filter groups (having is a kind of where but after make the group by), or you can use a subquery. Try something like this:

select Price, Date
 from table1
 where Code = 4235
and Date = (SELECT Max(Date) -1 FROM table1)
 group by Price
0
 
LVL 16

Expert Comment

by:Surendra Nath
ID: 39818669
you need to write it as below

select Price, Date
 from table1
 where Code = 4235
 group by Price
having Date = Max(Date) -1

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0
 
LVL 12

Expert Comment

by:Tony303
ID: 39818759
I think MAX(Date) -1 is incorrect.

That will be the day before the last date, potentially no data.

What is needed is a Top 2 selection.
To derive the 2nd newest date...


SELECT MIN(a.Date) AS SecondNewestDate 
FROM 
(SELECT TOP 2 Date
FROM Table
WHERE Code = 4235
ORDER BY Date DESC) a

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T
0
 

Author Comment

by:WorknHardr
ID: 39819843
No matter which solution I use, doesn't work when I join tables.
0
What is SQL Server and how does it work?

The purpose of this paper is to provide you background on SQL Server. It’s your self-study guide for learning fundamentals. It includes both the history of SQL and its technical basics. Concepts and definitions will form the solid foundation of your future DBA expertise.

 
LVL 16

Accepted Solution

by:
Surendra Nath earned 250 total points
ID: 39821113
check this out

DECLARE @T TABLE 
(
Price INT, Date Datetime,code INT
)

insert into @T VALUES (123,GETDATE(),4235)
insert into @T VALUES (124,GETDATE(),4235)
insert into @T VALUES (228,GETDATE()-1,4235)
insert into @T VALUES (223,GETDATE()-1,4235)
insert into @T VALUES (128,GETDATE()-2,4235)
insert into @T VALUES (123,GETDATE()-2,4235)

-- all the above code is used to setup temporary or dummy data...

SELECT T1.* FROM @T T1
,(
select Max(Date)    date
from @t
where Code = 4235
) T2
WHERE T1.code = 4235 and t1.date = t2.date -1 

Open in new window

0
 

Author Comment

by:WorknHardr
ID: 39821378
I changed the Price and Date values to a more realistic test. I just need to Join more tables to see if it still works as well.


DECLARE @T TABLE
(
Price INT, Date Datetime,code INT
)

insert into @T VALUES (300,GETDATE()-1,4235)
insert into @T VALUES (200,GETDATE()-2,4235)
insert into @T VALUES (100,GETDATE()-3,4235)
insert into @T VALUES ( 50,GETDATE()-4,4235)

-- all the above code is used to setup temporary or dummy data...

[Max Date]
SELECT Top 1 T1.* FROM @T T1
,(
select Max(Date)    date
from @t
where Code = 4235
) T2
WHERE T1.code = 4235 and t1.date = t2.date

[Max Date -1]
SELECT Top 1 T1.* FROM @T T1
,(
select Max(Date)    date
from @t
where Code = 4235
) T2
WHERE T1.code = 4235 and t1.date = t2.date -1
0
 
LVL 31

Assisted Solution

by:awking00
awking00 earned 250 total points
ID: 39822035
select price, date from
(select price, date, row_number() over (partition by code order by date desc) rn
 from table1
 where code = 4235) as x
where x.rn <= 2
0
 

Author Closing Comment

by:WorknHardr
ID: 39833701
thank you all
0

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What is SQL Server and how does it work?

The purpose of this paper is to provide you background on SQL Server. It’s your self-study guide for learning fundamentals. It includes both the history of SQL and its technical basics. Concepts and definitions will form the solid foundation of your future DBA expertise.

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