I have a complex query and which may return more than one record per group. There is a field that has a numeric sequential number. If in a group there is more than one record returned I just want the record with the highest sequential number.
I’ve tried using the SQL MAX function, but if I try to add more than one field it returns all records, instead of the one with the highest sequential field in that group.
I am trying to accomplish this in MS Access.
Edit: 4/5/11
Trying to create a table as an example of what I am trying to do
I have the following table:
tblItemTrans
ItemID(PK)
Eventseq(PK)
ItemTypeID
UserID
Eventseq is a number field that increments for each ItemID. (Don’t ask me why, that’s how the table was created.) Each ItemID can have one or many Evenseq’s. I only need the last record (max(Eventseq)) PER each ItemTypeID.
Hope this helps any.
SELECT A.*
FROM YourTable A
INNER JOIN (SELECT GroupColumn, MAX(SequentialColumn) MaxSeq
FROM YourTable
GROUP BY GroupColumn) B
ON A.GroupColumn = B.GroupColumn AND A.SequentialColumn = B.MaxSeq
If your SequentialNumber is an ID (unique across the table), then you could use
select *
from tbl
where seqnum in (
select max(seqnum) from tbl
group by groupcolumn)
If it is not, an alternative to Lamak's query is the Access domain function DMAX
select *
from tbl
where seqnum = DMAX("seqnum", "tbl", "groupcolumn='" & groupcolumn & "'")
Note: if the groupcolumn is a date, use # instead of single quotes ' in the above, if it is a numeric, remove the single quotes.
Related
I have two tables:
And I want to add GTIN from table 2 to table 1 based on brand name. Though I cant use = or like because as you see in highlighted row they are not fully matched.
For example
Second row in table 1, suppose to have first GTIN from table 2 because both are Ziagen 300mg tablet. However all of what I tried failed to match all row correctly.
Postgres has a pg_trgm module described here. Start with a cross join joining both tables and calculate the similarity(t1.brand,t2.brand) function, which returns the real number.
Next filter the results based on some heuristic number. Then narrow down with choosing single best match using row_number() window function.
The results might be not accurate, you could improve it by taking generic similarity into account as well.
with cross_similarity(generic1,brand1,gtin,brand2,generic2,sim) as (
select *, similarity(t1.brand, t2.brand) as sim
from t1,
t2
where similarity(t1.brand, t2.brand) > 0
)
, max_similarity as (
select *,
row_number() over (partition by gtin order by sim desc) as best_match_rank
from cross_similarity
)
select * from max_similarity where best_match_rank =1;
I want to return all the rows from a table which are unique. I.e. if a certain field in two rows contain the same name, that name shouldn't be shown.
Since you want only the uniques names (and not an unique row for every names like you could have with DISTINCT), you have to use a GROUP BY and a HAVING (instead of a WHERE, because your parameter is the result of a function, not a variable) :
SELECT name FROM myTable GROUP BY name HAVING COUNT(name) = 1
SELECT DISTINCT column_name FROM table
If you want the complete rows, then use row_number() or distinct on:
select distinct on (name) t.*
from table t
order by name;
can someone help me about counting rows in sql. I have a table, archive, in which I have bank account and status of that account. One account can have and usually have more records, in my count I have to use last record, not records before. Example:
account status
5552222 A
5552222 B
5552222 A
**5552222 B**
4445896 A
4445896 B
**4445896 A**
I have to use this who are bold. Based on this there is one B(blocked) and one A(active) account. I have column datetime, which can tell me what is last record. I just need query to count that
Assuming you want to count based on the most current row for an account:
SELECT tab.status,
COUNT(*)
FROM tab JOIN
(
SELECT account, MAX(datetime) AS maxdate
FROM tab
GROUP BY account
) AS dt
ON tab.account = dt.account
AND tab.datetime = dt.maxtime
GROUP BY tab.Status
SELECT COUNT(*)
FROM yourTable
WHERE Status='B'
or
WHERE AccountName LIKE '%B'
Edit: After OP modified the question to include the table data.
So, the problem is that the same account number can occur multiple times, and you want to count on the basis of last status of the account.
If the account is currently blocked, you would like to count it, irrespective of the number of times it gets blocked earlier.
Assumption: You have a date type column in your table which shows the date when the record's (with new status value) was inserted (or it may be an identity field which keeps track of the order of records created in the table)
The query will be:
SELECT COUNT (*)
FROM
(
SELECT DISTINCT
acNumber,
( SELECT Max(identityField_or_dateField)
FROM tableName t
WHERE t.acNumber = t2.acNumber AND Status='B')
FROM tableName t2
WHERE
( SELECT Max(identityField_or_dateField)
FROM tableName t
WHERE t.acNumber = t2.acNumber AND Status='B') IS NOT NULL
) tblAlias
Glad to help! Please remember to accept the answer if you found it helpful.
I would like to see a most concise way to do what is outlined in this SO question: Sum values from multiple rows into one row
that is, combine multiple rows while summing a column.
But how to then delete the duplicates. In other words I have data like this:
Person Value
--------------
1 10
1 20
2 15
And I want to sum the values for any duplicates (on the Person col) into a single row and get rid of the other duplicates on the Person value. So my output would be:
Person Value
-------------
1 30
2 15
And I would like to do this without using a temp table. I think that I'll need to use OVER PARTITION BY but just not sure. Just trying to challenge myself in not doing it the temp table way. Working with SQL Server 2008 R2
Simply put, give me a concise stmt getting from my input to my output in the same table. So if my table name is People if I do a select * from People on it before the operation that I am asking in this question I get the first set above and then when I do a select * from People after the operation, I get the second set of data above.
Not sure why not using Temp table but here's one way to avoid it (tho imho this is an overkill):
UPDATE MyTable SET VALUE = (SELECT SUM(Value) FROM MyTable MT WHERE MT.Person = MyTable.Person);
WITH DUP_TABLE AS
(SELECT ROW_NUMBER()
OVER (PARTITION BY Person ORDER BY Person) As ROW_NO
FROM MyTable)
DELETE FROM DUP_TABLE WHERE ROW_NO > 1;
First query updates every duplicate person to the summary value. Second query removes duplicate persons.
Demo: http://sqlfiddle.com/#!3/db7aa/11
All you're asking for is a simple SUM() aggregate function and a GROUP BY
SELECT Person, SUM(Value)
FROM myTable
GROUP BY Person
The SUM() by itself would sum up the values in a column, but when you add a secondary column and GROUP BY it, SQL will show distinct values from the secondary column and perform the aggregate function by those distinct categories.
i have loanTable that contain two field loan_id and status
loan_id status
==============
1 0
2 9
1 6
5 3
4 5
1 4 <-- How do I select this??
4 6
In this Situation i need to show the last Status of loan_id 1 i.e is status 4. Can please help me in this query.
Since the 'last' row for ID 1 is neither the minimum nor the maximum, you are living in a state of mild confusion. Rows in a table have no order. So, you should be providing another column, possibly the date/time when each row is inserted, to provide the sequencing of the data. Another option could be a separate, automatically incremented column which records the sequence in which the rows are inserted. Then the query can be written.
If the extra column is called status_id, then you could write:
SELECT L1.*
FROM LoanTable AS L1
WHERE L1.Status_ID = (SELECT MAX(Status_ID)
FROM LoanTable AS L2
WHERE L2.Loan_ID = 1);
(The table aliases L1 and L2 could be omitted without confusing the DBMS or experienced SQL programmers.)
As it stands, there is no reliable way of knowing which is the last row, so your query is unanswerable.
Does your table happen to have a primary id or a timestamp? If not then what you want is not really possible.
If yes then:
SELECT TOP 1 status
FROM loanTable
WHERE loan_id = 1
ORDER BY primaryId DESC
-- or
-- ORDER BY yourTimestamp DESC
I assume that with "last status" you mean the record that was inserted most recently? AFAIK there is no way to make such a query unless you add timestamp into your table where you store the date and time when the record was added. RDBMS don't keep any internal order of the records.
But if last = last inserted, that's not possible for current schema, until a PK addition:
select top 1 status, loan_id
from loanTable
where loan_id = 1
order by id desc -- PK
Use a data reader. When it exits the while loop it will be on the last row. As the other posters stated unless you put a sort on the query, the row order could change. Even if there is a clustered index on the table it might not return the rows in that order (without a sort on the clustered index).
SqlDataReader rdr = SQLcmd.ExecuteReader();
while (rdr.Read())
{
}
string lastVal = rdr[0].ToString()
rdr.Close();
You could also use a ROW_NUMBER() but that requires a sort and you cannot use ROW_NUMBER() directly in the Where. But you can fool it by creating a derived table. The rdr solution above is faster.
In oracle database this is very simple.
select * from (select * from loanTable order by rownum desc) where rownum=1
Hi if this has not been solved yet.
To get the last record for any field from a table the easiest way would be to add an ID to each record say pID. Also say that in your table you would like to hhet the last record for each 'Name', run the simple query
SELECT Name, MAX(pID) as LastID
INTO [TableName]
FROM [YourTableName]
GROUP BY [Name]/[Any other field you would like your last records to appear by]
You should now have a table containing the Names in one column and the last available ID for that Name.
Now you can use a join to get the other details from your primary table, say this is some price or date then run the following:
SELECT a.*,b.Price/b.date/b.[Whatever other field you want]
FROM [TableName] a LEFT JOIN [YourTableName]
ON a.Name = b.Name and a.LastID = b.pID
This should then give you the last records for each Name, for the first record run the same queries as above just replace the Max by Min above.
This should be easy to follow and should run quicker as well
If you don't have any identifying columns you could use to get the insert order. You can always do it like this. But it's hacky, and not very pretty.
select
t.row1,
t.row2,
ROW_NUMBER() OVER (ORDER BY t.[count]) AS rownum from (
select
tab.row1,
tab.row2,
1 as [count]
from table tab) t
So basically you get the 'natural order' if you can call it that, and add some column with all the same data. This can be used to sort by the 'natural order', giving you an opportunity to place a row number column on the next query.
Personally, if the system you are using hasn't got a time stamp/identity column, and the current users are using the 'natural order', I would quickly add a column and use this query to create some sort of time stamp/incremental key. Rather than risking having some automation mechanism change the 'natural order', breaking the data needed.
I think this code may help you:
WITH cte_Loans
AS
(
SELECT LoanID
,[Status]
,ROW_NUMBER() OVER(ORDER BY (SELECT 1)) AS RN
FROM LoanTable
)
SELECT LoanID
,[Status]
FROM LoanTable L1
WHERE RN = ( SELECT max(RN)
FROM LoanTable L2
WHERE L2.LoanID = L1.LoanID)