I am trying to update a table in my database with another row from another table. I have two parameters one being the ID and another being the row number (as you can select which row you want from the GUI)
this part of the code works fine, this returns one column of a single row.
(SELECT txtPageContent
FROM (select *, Row_Number() OVER (ORDER BY ArchiveDate asc) as rowid
from ARC_Content Where ContentID = #ContentID) as test
Where rowid = #rowID)
its just when i try to add the update/set it won't work. I am probably missing something
UPDATE TBL_Content
Set TBL_Content.txtPageContent = (select txtPageContent
FROM (select *, Row_Number() OVER (ORDER BY ArchiveDate asc) as rowid
from ARC_Content Where ContentID = #ContentID) as test
Where rowid = #rowID)
Thanks for the help! (i have tried top 1 with no avail)
I see a few issues with your update. First, I don't see any joining or selection criteria for the table that you're updating. That means that every row in the table will be updated with this new value. Is that really what you want?
Second, the row number between what is on the GUI and what you get back in the database may not match. Even if you reproduce the query used to create your list in the GUI (which is dangerous anyway, since it involves keeping the update and the select code always in sync), it's possible that someone could insert or delete or update a row between the time that you fill your list box and send that row number to the server for the update. It's MUCH better to use PKs (probably IDs in your case) to determine which row to use for updating.
That said, I think that the following will work for you (untested):
;WITH cte AS (
SELECT
txtPageContent,
ROW_NUMBER() OVER (ORDER BY ArchiveDate ASC) AS rowid
FROM
ARC_Content
WHERE
ContentID = #ContentID)
UPDATE
TC
SET
txtPageContent = cte.txtPageContent
FROM
TBL_Content TC
INNER JOIN cte ON
rowid = #rowID
Related
In the temp table there are only two columns available. I would like to get the most recent ID for each load, as shown in the picture below.
I have tried this but it doesn't give me the answer I need.
select max(rn_plus_1),a.load, a.id from( select a.load,
a.id,
ROW_NUMBER() over(order by a.id desc) rn from max_num a group by load
, id) a
TEMP_TABLE lacks a sequential primary key or any other indicator for order of insertion. So it is not possible to get the latest ID for a LOAD using the columns of the table itself.
However, there is one option: ORA_ROWSCN(). This is a pseudo-column which identifies the System Change Number for the transaction which changed the table. So we can reconstruct the order of insertion by sorting the table on ORA_ROWSCN.
There are some caveats:
By default the SCN applies to the block level. Consequently all the rows in a block have the same SCN. It's a good enough approximation for wide tables but hopeless for a two-column toy like TEMP_TABLE. We can track SCN at the row level but only if the table is created with ROWDEPENDENCIES. The default is NOROWDEPENDENCIES. Unfortunately, we cannot use ALTER TABLE here. You will need to drop and recreate the table (*) to enable ROWDEPENDENCIES.
The SCN applies to the transaction. This means the solution will only work if each row in TEMP_TABLE is inserted in a separate transaction.
Obviously this is only possible if TEMP_TABLE is an actual table and not a view or some other construct.
Given all these criteria are satisfied here is a query which will give you the result set you want:
select load, id
from ( select load
, id
, row_number() over (partition by load order by ora_rowscn desc) as rn
from temp_table
)
where rn = 1
There is a demo on db<>fiddle. Also, the same demo except TEMP_TABLE defined with NOROWDEPENDENCIES, which produces the wrong result.
(*) If you need to keep the data in TEMP_TABLE the steps are:
rename TEMP_TABLE to whatever;
create table TEMP_TABLE as select * from whatever rowdependencies;
drop table whatever;
However, the SCN will be the same for the existing rows. If that matters you'll have to insert each row one at a time, in the order you wish to preserve, and commit after each insert.
I tried to do an UPDATE statement with a random row from another table. I know this question has been asked before (here), but it doesn't seem to work for me.
I should update each row with a different value from the other table. In my case it only gets one random row from a table and puts that in every row.
UPDATE dbo.TABLE_CHARGE
SET COLRW_STREET =
(SELECT TOP 1 COLRW_STREET FROM CHIEF_PreProduction.dbo.TABLE_FAKESTREET
ORDER BY ABS(CHECKSUM(NewId())%250))
Thanks in advance!
I took a liberty to assume that you have ID field in your TABLE_CHARGE table. This is probably not the most efficient way, but seems to work:
WITH random_values as
(
SELECT t.id, t.COLRW_STREET, t.random_street FROM (
SELECT c.id, c.COLRW_STREET,
f.COLRW_STREET as random_street, ROW_NUMBER() OVER (partition by c.id ORDER BY ABS(CHECKSUM(NewId())%250)) rn
FROM table_charge c, TABLE_FAKESTREET f) t
WHERE t.rn = 1
)
UPDATE random_values SET COLRW_STREET = random_street;
SQL Fiddle demo
Your original code did not work because when yo do ... SET x = (SELECT TOP 1 ..) database does OUTER JOIN of your target table with one TOP row, which means that one single row is applied to all rows in your target table. Hence you have same value in all rows.
Following query demonstrates what is happening in the UPDATE:
SELECT * FROM
TABLE_CHARGE tc,
(SELECT TOP 1 COLRW_STREET as random_street FROM TABLE_FAKESTREET
ORDER BY ABS(CHECKSUM(NewId())%250)) t
My solution gets all fake records ordered randomly for each record in target table and only selects the first one per ID.
I can't seem to get this query to work I am pretty sure I have it correct but i keep coming up with errors. I am trying to create a update query to the rows and they way they are sorted by using a where clause to a specific section as well as a join.
Here is my query:
With cte As
(
SELECT Products.Products.PartNumber, Products.Prices.ProductID, Products.Prices.CODE, Products.Prices.Price
ROW_NUMBER() OVER (ORDER BY Price DESC) AS RN
FROM Test
JOIN Products.Prices
ON Products.Products.ID = Products.Prices.ProductID
where partnumber like 'l2%'
Order by Price Desc
)
UPDATE cte SET Number=RN
Thank you.
Instead of updating the row in the table, you could create a VIEW using your ORDER BY query and other queries could check the view instead of the row.
If you want to stick to just your table, you need to check and make sure the ROW ID being set isn't conflicting with any other row. For instance, if you ORDER BY and find row with ID=6 to be the first in the new query, you update it with ID=1. However, row 1 already has ID=1, and that conflicts with your new row ID (Previously row ID=6).
I'm trying change existing schema to add new column.
Here is my case - http://sqlfiddle.com/#!3/06c58/1
Value of Order column is int, which should represent order of items on UI from 1 to COUNT(Id) if I'm grouping TemplateId.
I see 2 possible solutions - make Order calculated field or use Cursor to update it.
Which one is better? And if update using cursor win -
May I know how to have such update ?
One way I can think of it is this:
Start a transaction
Insert into columns apart from Order
Update the table to set Order values
Commit transaction if everything is OK, else rollback.
You won't need to directly deal with cursors to do this, and the operation will be atomic in a way, since it's wrapped in a transaction block.
The update itself can be done something like this:
;with ord as
(Select id, row_number() over (partition by templateid order by selectedfieldid) rn from yourtable)
Update dbo.titlefields
Set order = rn - 1 --ROW_NUMBER() starts at 1 but we want to start at 0
From dbo.titlefields t inner join
ord x on t.id = x.id
Please let me know if I have understood your requirement correctly, and I will update my answer if that is not so.
What's the best way to delete all rows from a table in sql but to keep n number of rows on the top?
DELETE FROM Table WHERE ID NOT IN (SELECT TOP 10 ID FROM Table)
Edit:
Chris brings up a good performance hit since the TOP 10 query would be run for each row. If this is a one time thing, then it may not be as big of a deal, but if it is a common thing, then I did look closer at it.
I would select ID column(s) the set of rows that you want to keep into a temp table or table variable. Then delete all the rows that do not exist in the temp table. The syntax mentioned by another user:
DELETE FROM Table WHERE ID NOT IN (SELECT TOP 10 ID FROM Table)
Has a potential problem. The "SELECT TOP 10" query will be executed for each row in the table, which could be a huge performance hit. You want to avoid making the same query over and over again.
This syntax should work, based what you listed as your original SQL statement:
create table #nuke(NukeID int)
insert into #nuke(Nuke) select top 1000 id from article
delete article where not exists (select 1 from nuke where Nukeid = id)
drop table #nuke
Future reference for those of use who don't use MS SQL.
In PostgreSQL use ORDER BY and LIMIT instead of TOP.
DELETE FROM table
WHERE id NOT IN (SELECT id FROM table ORDER BY id LIMIT n);
MySQL -- well...
Error -- This version of MySQL does not yet support 'LIMIT &
IN/ALL/ANY/SOME subquery'
Not yet I guess.
Here is how I did it. This method is faster and simpler:
Delete all but top n from database table in MS SQL using OFFSET command
WITH CTE AS
(
SELECT ID
FROM dbo.TableName
ORDER BY ID DESC
OFFSET 11 ROWS
)
DELETE CTE;
Replace ID with column by which you want to sort.
Replace number after OFFSET with number of rows which you want to keep.
Choose DESC or ASC - whatever suits your case.
I think using a virtual table would be much better than an IN-clause or temp table.
DELETE
Product
FROM
Product
LEFT OUTER JOIN
(
SELECT TOP 10
Product.id
FROM
Product
) TopProducts ON Product.id = TopProducts.id
WHERE
TopProducts.id IS NULL
This really is going to be language specific, but I would likely use something like the following for SQL server.
declare #n int
SET #n = SELECT Count(*) FROM dTABLE;
DELETE TOP (#n - 10 ) FROM dTable
if you don't care about the exact number of rows, there is always
DELETE TOP 90 PERCENT FROM dTABLE;
I don't know about other flavors but MySQL DELETE allows LIMIT.
If you could order things so that the n rows you want to keep are at the bottom, then you could do a DELETE FROM table LIMIT tablecount-n.
Edit
Oooo. I think I like Cory Foy's answer better, assuming it works in your case. My way feels a little clunky by comparison.
I would solve it using the technique below. The example expect an article table with an id on each row.
Delete article where id not in (select top 1000 id from article)
Edit: Too slow to answer my own question ...
Refactored?
Delete a From Table a Inner Join (
Select Top (Select Count(tableID) From Table) - 10)
From Table Order By tableID Desc
) b On b.tableID = A.tableID
edit: tried them both in the query analyzer, current answer is fasted (damn order by...)
Better way would be to insert the rows you DO want into another table, drop the original table and then rename the new table so it has the same name as the old table
I've got a trick to avoid executing the TOP expression for every row. We can combine TOP with MAX to get the MaxId we want to keep. Then we just delete everything greater than MaxId.
-- Declare Variable to hold the highest id we want to keep.
DECLARE #MaxId as int = (
SELECT MAX(temp.ID)
FROM (SELECT TOP 10 ID FROM table ORDER BY ID ASC) temp
)
-- Delete anything greater than MaxId. If MaxId is null, there is nothing to delete.
IF #MaxId IS NOT NULL
DELETE FROM table WHERE ID > #MaxId
Note: It is important to use ORDER BY when declaring MaxId to ensure proper results are queried.