I have a table like so:
Id, Comment, LastUpdatedDate
I'm tyring to select the latest comment for that id. The table can have many comments on that id with different dates but I'm trying to get the latest date out of there. I've tried the following with no success:
SELECT tt.*
FROM tagtestresultcomment tt
INNER JOIN
(
SELECT tag_id, MAX(last_update) AS MaxDateTime
FROM tagtestresultcomment
GROUP BY tag_id
) groupedtt ON tt.tag_id = groupedtt.tag_id AND tt.last_update = groupedtt.MaxDateTime
order by tag_id
Does anyone have any ideas of how to achieve this?
Thanks!
It sounds like you want only the latest comment for each tag_id? In which case, here is one approach you can use from SQL 2005 and on:
;WITH CTE AS
(
SELECT *,
ROW_NUMBER() OVER(PARTITION BY tag_id ORDER BY last_update DESC) AS RowNo
FROM TagTestResultComment
)
SELECT * FROM CTE WHERE RowNo = 1
try this
Select * from tagtestresultcomment where last_update in
(select max(last_update) from tagtestresultcomment group by tag_id)
your query code is too redundant. first
tt.tag_id = groupedtt.tag_id AND tt.last_update = groupedtt.MaxDateTime
it's enough just
tt.tag_id = groupedtt.tag_id
and second, it's enough just
SELECT [desired field list extcept last_update and ],
tag_id,
MAX(last_update) AS MaxDateTime
FROM
tagtestresultcomment
group by
tag_id, [desired field list extcept last_update and tag_id]
at all to achieve your objective
I have tried something like this:
declare #tagtestresultcomment table
(
id int
, comment varchar(50)
,LastUpdatedDate datetime
)
--==== Populate table
insert into #tagtestresultcomment(id,comment,LastUpdatedDate)
select 1,'My name is Arthur','2011-06-09 00:00:00' union all
select 2,'My name is DW','2011-06-19 00:00:00' union all
select 2,'Arthur is my brother','2011-06-21 00:00:00' union all
select 1,'I have a sister named DW','2011-06-21 00:00:00' union all
select 3,'I am Muffy','2011-06-14 00:00:00' union all
select 3,'I like sports','2011-06-14 00:00:00'
-- SELECT stmt
select * from #tagtestresultcomment t
join
(
select id, MAX(lastupdateddate) as LastUpdatedDate from #tagtestresultcomment group by id
) m
on t.id = m.id
and t.LastUpdatedDate = m.LastUpdatedDate
The "MAX" group function wasn't working for me, so I used a sub-query. I had trouble wrapping my head around your single table example, so I'm using a common parent-child 1-to-many relationship with a blog and comment tables as an example.
SELECT
b.id,
b.content,
c.id,
c.blog_id,
c.content,
c.last_update
FROM blog b
INNER JOIN blog_comment c
ON b.id = c.blog_id AND c.id = (
SELECT TOP 1 id FROM blog_comment WHERE blog_id = b.id ORDER BY last_update DESC
)
The query takes a hit on my sub-query, as it will call that "SELECT TOP 1" query for each record in the blog table. I'd like to hear of a faster, more efficient example if possible.
Related
I am looking to left join another table because there are two columns in that table that I need to add to my query..how can I left join onto my existing query? For example the query I am using is similar to the one below..
select subject, sum(cnt_daily) as cnt,
min(cnt_daily) as min_cnt_daily, max(cnt_daily) as max_cnt_daily
from (
select study_date, subject, count(*) as cnt_daily
from mytable
where study_date >= '2022-01-01'
group by study_date, subject
) t
group by subject
I tried
select *
from mytable
left join table2
on mytable.id= table1.id
order by table1.id;
But i know this isnt right
You may use CTE:
WITH t AS (
select study_date, subject, count(*) as cnt_daily
from mytable
where study_date >= '2022-01-01'
group by study_date, subject
)
select subject, sum(cnt_daily) as cnt,
min(cnt_daily) as min_cnt_daily, max(cnt_daily) as max_cnt_daily
from t
group by subject
This could encourage reuse of the query inside CTE.
I have a table that has two IDs within it named FamilyID and PersonID. I need to be able to repeat these rows with all combinations, as the below screenshot shows noting that each of the numbers get an extra row.
Here is some SQL to create the table with some sample data. There is no set number of occurrences that could occur.
Anyone aware of how we could be achieved?
CREATE TABLE #TempStackOverflow
(
FamilyID int,
PersonID int
)
insert into #TempStackOverflow
(
FamilyID,
PersonID
)
select
1012,
1
union
select
1013,
1
union
select
1014,
1
union
select
1015,
2
union
select
14774,
3
union
select
1019,
5
I understand that you need some sort of a complete list of matches within groups, but honestly, it would be much better if you would explain the business context, using plain English, in the first place.
The following query seems to produce your sample result:
with cte as (
select a.FamilyID, a.PersonID, a.PersonID as [GroupId] from #TempStackOverflow a
union all
select b.PersonID, b.FamilyID, b.PersonID from #TempStackOverflow b
)
select distinct c.FamilyID, s.PersonID
from cte c
inner join cte s on s.GroupId = c.GroupId
where c.FamilyID != s.PersonID;
Here is the simplest version I can come up with that groups the items by PersonId, as you do above. Obviously if you don't want that, then you can remove the outer query.
SELECT FamilyId,
PersonID
FROM (
SELECT FamilyId, PersonId, PersonID as SortBy
FROM #TempStackOverflow t1
UNION
SELECT PersonId, FamilyId, PersonId as SortBy
FROM #TempStackOverflow t1
UNION
SELECT t1.FamilyID, t2.FamilyID, t1.PersonID as SortBy
FROM #TempStackOverflow t1
FULL OUTER JOIN #TempStackOverflow t2
ON t1.PersonID = t2.PersonID
WHERE t1.FamilyID != t2.FamilyID
) as Src
ORDER BY SortBy
This query is fine works.
SELECT * FROM TABLE WHERE 330110042 IN (iItem01,iItem02,iItem03,iItem04,iItem05,iItem_1,iItem_2,iItem_3,iItem_4,iItem_5,iItem_6,iItem_7,iItem_8,iItem_9,iItem_10,iItem_11,iItem_12,iItem_13,iItem_14,iItem_15,iItem_16,iItem_17,iItem_18,iItem_19,iItem_20,iItem_21,iItem_22,iItem_23,iItem_24,iItem_25,iItem_26,iItem_27,iItem_28,iItem_29,iItem_30)
But this query didnt work.
SELECT * FROM TABLE WHERE 330110042, 330110002, 330110002 IN (iItem01,iItem02,iItem03,iItem04,iItem05,iItem_1,iItem_2,iItem_3,iItem_4,iItem_5,iItem_6,iItem_7,iItem_8,iItem_9,iItem_10,iItem_11,iItem_12,iItem_13,iItem_14,iItem_15,iItem_16,iItem_17,iItem_18,iItem_19,iItem_20,iItem_21,iItem_22,iItem_23,iItem_24,iItem_25,iItem_26,iItem_27,iItem_28,iItem_29,iItem_30)
How i work in SQL Server?
It's difficult to tell your exact goal here, but one possibility would be to turn the list of values into a table structure of its own. A Common Table Expression might work:
;WITH Ids AS
(
SELECT 330110042 AS Id
UNION ALL
SELECT 330110002
)
SELECT t.*
FROM [Table] t
INNER JOIN Ids i ON t.iItem01 = i.Id OR t.iItem02 = i.Id OR...
But, maybe a solution with UNPIVOT would be more elegant. I presume that your table has a primary key column called Id:
;WITH Unpivoted AS
(
SELECT Id, ColName, ColValue
FROM (SELECT Id, iItem01, iItem02, iItem03
FROM [Table] t) p
UNPIVOT
(ColValue FOR ColName IN (iItem01, iItem02, iItem03)) AS unpvt
)
SELECT t.*
FROM [Table] t
WHERE EXISTS (SELECT 1 FROM Unpivoted u
WHERE t.Id = u.Id
AND u.ColValue IN (330110042, 330110002))
Of course, you would add all the necessary columns. I added only the first three for this example.
i have many duplicate job id but entry date is can not be duplicate. i need to fetch always unique job id based on last entry date. i have solved it with the below query but like to know is there any better way to form the same sql when data would be huge for best performance. please guide me thanks.
SELECT A.JID,A.EntryDate,RefundDate,Comments,Refund, ActionBy
FROM (
(
select JID, Max(EntryDate) AS EntryDate
from refundrequested
GROUP BY JID
) A
Inner JOIN
(
SELECT JID,ENTRYDATE,refundDate,Comments,refund,ActionBy
from refundrequested
) B
ON A.JID=B.JID AND A.EntryDate = B.EntryDate
)
Using the row_number() function is usually a bit faster:
select *
from (
select row_number() over (partition by jid
order by EntryDate desc) as rn
, *
from refundrequested
) as SubQueryAlias
where rn = 1
Query:
SELECT t1.JID,
t1.EntryDate,
t1.RefundDate,
t1.Comments,
t1.Refund,
t1.ActionBy
FROM refundrequested t1
LEFT JOIN refundrequested t2
ON t2.JID = t1.JID
AND t2.EntryDate > t1.EntryDate
WHERE t2.JID is null
select first(orderid), accountid
from [Order]
group by AccountId
order by DateCreated desc
first() is invalid function.
max() does not work for unique identifiers
How would I get the last orderid created for all accounts? Thanks.
Something like (untested):
;WITH CTE_LatestOrders AS (
select accountid, lastcreated = max(datecreated)
from [Order]
group by accountid
)
select
accountid, orderid
from
[Orders] o
join CTE_LatestOrders l
on o.AccountID = l.AccountID
and o.datecreated = l.lastcreated
Max() does work for unique identifiers as of MS SQL 2012
You can proceed with below as well.
Select Temp.orderid, T.AccountId, T.DateCreated
From
(
Select AccountId, max(DateCreated) as DateCreated
From [Order]
Group By AccountId
)T
Inner Join [Order] Temp on Temp.AccountId = T.AccountId
AND Temp.DateCreated = T.DateCreated
A CTE is not a UDT/temp table; think of a CTE as a view that is defined only for your current query. Just like a view, a CTE is expanded and folded into the overall query plan. Global optimization will still occur, but do not think that just because you use a CTE you will only execute the query once. Here is a trivial example that fits in this space: WITH vw AS ( SELECT COUNT(*) c FROM Person ) SELECT a.c, b.c FROM vw a, vw b; The query plan will clearly show two scans/aggregations and a join instead of just projecting the same result twice.