SELECT MAX Date T-SQL Subquery - sql

Question

I am attempting to SELECT rows from a table using a query like this
SELECT pminf_member, pminf_schmem
, pminf_date, pminf_fund
, pminf_cont, pminf_rate
, pminf_matrix
FROM pe_minvf
WHERE (pminf_member = 4380)
AND (pminf_schmem = 'M')
AND (pminf_date <= '03/30/2011')
AND (pminf_date =
(SELECT MAX(pminf_date) AS Expr1
FROM pe_minvf AS pe_minvf_1
WHERE (pminf_member = 4380)
)
)
AND (pminf_fund = 'LIFESTYLE')
What I should be getting from my subquery (I think) is a date of '01/01/2011' but when I run my query I am getting no results back.
If I replace the subquery with the hardcoded date I get the correct rows returned. For example
SELECT pminf_member, pminf_schmem
, pminf_date, pminf_fund
, pminf_cont, pminf_rate
, pminf_matrix
FROM pe_minvf
WHERE (pminf_member = 4380)
AND (pminf_schmem = 'M')
AND (pminf_date <= '03/30/2011')
AND (pminf_date = '01/01/2011')
AND (pminf_fund = 'LIFESTYLE')
This query returns the correct results.
Any ideas why the subquery is not returning the max date or if it is, why am I getting no rows back?
Thanks,
Tristan

Answer 1

You filter on different conditions in your queries.
It's pminf_fund = 'LIFESTYLE' in the subquery but pminf_schmem = 'M' in the outer query.
Also, you limit the date in the outer query and don't do it in the subquery.
If you just need the most recent record up to '03/30/2011', use this:
SELECT TOP 1
pminf_member, pminf_schmem, pminf_date, pminf_fund, pminf_cont, pminf_rate, pminf_matrix
FROM pe_minvf
WHERE pminf_member = 4380
AND pminf_schmem = 'M'
AND pminf_fund = 'LIFESTYLE'
AND pminf_date <= '03/30/2011'
ORDER BY
pminf_date DESC

Answer 2

SELECT pminf_member, pminf_schmem
, pminf_date, pminf_fund
, pminf_cont, pminf_rate
, pminf_matrix
FROM pe_minvf
WHERE (pminf_member = 4380)
AND (pminf_schmem = 'M')
AND (pminf_date =
(SELECT MAX(pminf_date) AS Expr1
FROM pe_minvf AS p
WHERE (p.pminf_member = 4380) AND
p.pminf_date <= '03/30/2011'
)
)
AND (pminf_fund = 'LIFESTYLE')

Answer 3

The query:
SELECT MAX(pminf_date) AS Expr
FROM pe_minvf AS pe_minvf_1
WHERE (pminf_member = 4380)
;
returns '01/01/2011' or something else?
Perhaps you want the same conditions on the subquery as in th emain query:
SELECT MAX(pminf_date) AS Expr
FROM pe_minvf AS pe_minvf_1
WHERE (pminf_member = 4380)
AND (pminf_schmem = 'M')

Answer 4

use a subquery to limit rows returned instead of the where clause. Use this as the subquery:
(SELECT MAX(pminf_date) AS Expr1
FROM pe_minvf AS pe_minvf_1
WHERE (pminf_member = 4380)
Keep the query basically the same...
Select same_fields_as you_did_before
from pe_minvf
inner join
(SELECT MAX(pminf_date) AS Maxdate, tablekey
FROM pe_minvf AS pe_minvf_1
WHERE pminf_member = 4380) a on a.tablekey = pe_minvf.table_key
where same_where_clause_you_had
Make sense? I wasn't sure what your table_key was on pe_minvf...you'll have to insert that yourself. I find using subqueires adn inner joining to them is a more effective way of limiting rows then having a subquery in your where clause

Answer 5

Twelfth!
Thanks for the proper syntax... I used it to resolve my similar problem de-jur (of-the-day)
Unless I am wrong, what I have below will work.. If it doesn't I will fix it here...
In the example below the data fields name have been cleansed but the syntax worked very fast.
By the way, there are 20,480 distinct device_id
declare
#BegDate varchar(20)=(select cast(CONVERT(VARCHAR(20), getdate()-2,101) as varchar(20)) + ' 10:59:59 PM')
,#EndDate varchar(20)=(select cast(CONVERT(VARCHAR(20), getdate()-0,101) as varchar(20)) + ' 11:00:00 PM')
select f1.ABC_ConfigProcStatusID,f1.DeviceID,f1.DBfilename ,f1.LastUpdatedDate
from dbo.ABC_ConfigProcStatus f1
inner join
(select distinct DeviceID,max(LastUpdatedDate) as max_DeviceIDdte
from dbo.ABC_ConfigProcStatus
where [Status]=2
and DeviceID not in(select ExclusionDeviceIDs from ABC_ConfigDeviceIDExclusionList)
group by DeviceID) f2
on f2.max_DeviceIDdte = f1.LastUpdatedDate
where [Status]=2
and f2.DeviceID = f1.DeviceID
and f1.DeviceID not in(select ExclusionDeviceIDs from ABC_ConfigDeviceIDExclusionList)
and LastUpdatedDate between #BegDate and #EndDate
and left(upper(f1.DeviceID),3) in ('XYZ','ZKO')
order by f1.LastUpdatedDate