I am writing an AFTER INSERT Trigger on a table which is getting data from an Excel file, which has these three columns:
Tag_No ,Date ,Problem
The problem is that in this Excel File the Tag_No is not repeated when it is the same as the previous one. An example of this data is as follows:
Tag_No ,Date ,Problem
1 17-JUL-14 ABCS
18-JUL-14 asdf
2 17-JUL-14 ABCS
18-JUL-14 asdf
Tag_No will be empty if it is repeating like above. I would like to copy the above Tag_No for each row which I am inserting.
I would suggest solving this in a different way. Add an auto-incrementing column to the table. This will keep track of the order that the rows are put into the table. You can do this by defining a sequence and then using the sequence in the trigger.
Then, after the table is in the database, you can run an update to do what you want:
update table t
set tag = (select max(tag) keep (dense_rank first order by id desc)
from table t2
where t2.id < t.id and tag is not null
)
where tag is null;
Related
Say I have two customer tables which have pretty much the same columns. One of them is a temporal one which periodically updates the other one. That is, updates and additions to the records are done to the temporal table only. Say they're names are CUSTOMER, and CUSTOMER_TEMP.
The tables got information like ID, NAME, LAST_NAME, and ADDRESS.
This temporal table has three extra fields, TEMP_ID, RECORD_TYPE, and DATE. The record type is used to record whether there was an addition or an update. So the thing is I need to select the latest record from both tables. That involves several cases
Main table has record, but temporal doesn't -> Select main table record.
Main table has no record, but temporal does -> Select latest temporal table record.
Main table has record and temporal has an add record -> Select temporal table record.
Main table has record and temporal table has update record -> Select temporal table record.
Main table has record and temporal table has add and update record. -> Select temporal table update record.
Main table has record and temporal table has various update records. -> Select latest temporal table update record.
Main table has record and temporal table has add record and various update records. -> Select latest temporal table update record.
Now, I don't know whether this is a good flow or not. I was just told to make the query, so I don't have access to the DB, I believe I could make suggestions though. The thing is My SLQ knowledge is not enough to build this query. I know there's an INNER_JOIN involved, as well as a filter by date, and probably and EXIST, to check whether the record exist or not in the CUSTOMER_TEMP table. But I don't quite know how to build it. I'm working on .Net And SQLServer. Any help on it is quite appreciated.
select m.*, 0 as [rn]
from main m
where not exists (select 1 from temp where temp.id = m.id)
union
select tt.*
from ( select temp.*
, row_number() over (partition by id order by RECORD_TYPE desc, date desc) as rn
from temp
-- join main
-- on temp.ID = main.ID
) tt
where tt.rn = 1
if update does not sort last then need to do a trick like in the answer from Tom H
;WITH CTE_Latest_Temporal AS
(
SELECT
id,
name,
..., -- Put the rest of your columns here
ROW_NUMBER OVER (PARTITION BY id
ORDER BY
CASE record_type
WHEN 'Update' THEN 0
ELSE 1
END, date DESC) AS row_num
FROM
Customer_Temp
)
SELECT
M.id,
CASE WHEN T.id IS NOT NULL THEN T.name ELSE M.name END AS name,
... -- Similar CASE statements for the rest of your columns
FROM
Customer M
LEFT OUTER JOIN CTE_Latest_Temporal T ON
T.id = M.id AND
T.row_num = 1
The CASE statements can be replaced by a simple COALESCE(T.column, M.column) for any columns that cannot be NULL. I had to use the CASE to cover situations where the row might exist in the temp table but the column might be NULL in the temp table, but have a value in the main table.
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)
i have a table that somehow got duplicated. i basically want to delete all records that are duplicates, which is defined by a field in my table called SourceId. There should only be one record for each source ID.
is there any SQL that i can write that will delete every duplicate so i only have one record per Sourceid ?
Assuming you have a column ID that can tie-break the duplicate sourceid's, you can use this. Using min(id) causes it to keep just the min(id) per sourceid batch.
delete from tbl
where id NOT in
(
select min(id)
from tbl
group by sourceid
)
delete from table
where pk in (
select i2.pk
from table i1
inner join table i2
on i1.SourceId = i2.SourceId
)
good practice is to start with
select * from … and only later replace to delete from …
I have a status table, and another table containing additional data. My object IDs are the PK in the status table, so I need to insert those into the additional data table for each new row.
I need to insert a new row into my statusTable for each new listing, containing just constants.
declare #temp TABLE(listingID int)
insert into statusTable(status, date)
output Inserted.listingID into #temp
select 1, getdate()
from anotherImportedTable
This gets me enough new listing IDs to use.
I now need to insert the actual listing data into another table, and map each row to one of those listingIDs -
insert into listingExtraData(listingID, data)
select t.listingID, a.data
from #temp t, anotherImportedTable a
Now this obviously doesn't work, because otherDataTable and the IDs in #temp are unrelated... so I get far too many rows inserted.
How can I insert each row from anotherImportedTable into listingExtraData along with a unique newly created listingID? could I possibly trigger some more sql at the point I do the output in the first block of sql?
edit: thanks for the input so far, here's what the tables look like:
anotherImportedTable:
data
statusTable:
listingID (pk), status, date
listingExtraData:
data, listingID
You see that I only want to create one entry into statusTable per row in anotherImportedTable, then put one listingID with a row from anotherImportedTable into listingExtraData... I'm thinking that I might have to resort to a cursor perhaps?
Ok, here's how you can do it (if I'm right about what you actually want to do):
insert into listingExtraData(listingID, data)
select q1.listingID, q2.data
from
(select ListingID, ROW_NUMBER() OVER (order by ListingID) as rn from #temp t) as q1
inner join (select data, ROW_NUMBER() over (order by data) as rn from anotherImportedTable) q2 on q1.rn = q2.rn
In case you matching logic differs you will need to change sorting of anotherImportedTable. In case your match order can not be achieved by ordering anotherImportTable [in one way or another] then you're out of luck.
I have a table with some rows in. Every row has a date-field. Right now, it may be duplicates of a date. I need to delete all the duplicates and only store the row with the highest id. How is this possible using a SQL query?
Now:
date id
'07/07' 1
'07/07' 2
'07/07' 3
'07/05' 4
'07/05' 5
What I want:
date id
'07/07' 3
'07/05' 5
DELETE FROM table WHERE id NOT IN
(SELECT MAX(id) FROM table GROUP BY date);
I don't have comment rights, so here's my comment as an answer in case anyone comes across the same problem:
In SQLite3, there is an implicit numerical primary key called "rowid", so the same query would look like this:
DELETE FROM table WHERE rowid NOT IN
(SELECT MAX(rowid) FROM table GROUP BY date);
this will work with any table even if it does not contain a primary key column called "id".
For mysql,postgresql,oracle better way is SELF JOIN.
Postgresql:
DELETE FROM table t1 USING table t2 WHERE t1.date=t2.date AND t1.id<t2.id;
MySQL
DELETE FROM table
USING table, table as vtable
WHERE (table.id < vtable.id)
AND (table.date=vtable.date)
SQL aggregate (max,group by) functions almost always are very slow.