I do not have much experience in SQL so my question is probably simple:
On the result of a SELECT query, I need to UPDATE all records so that each record gets a value that is in the next record, as shown in the screenshot.
I would love to have an easy and ready code.
Note: I have the attached code:
SELECT ID, Title ,IDxNumber, LEAD(IdxNumber,1,0) Over(order by idxnumber) AS HotCode from MYTABLE
It works to display the data. But I want to update the data in the HotCode column in the table itself, not just display them.
Thanks
On SQL Server, we can use an updatable CTE. Assuming the HotCode column already exist in your table:
WITH cte AS (
SELECT *, LEAD(IdxNumber, 1, 0) OVER (ORDER BY idxnumber) AS HotCodeNew
FROM MYTABLE
)
UPDATE cte
SET HotCode = HotCodeNew;
Sorry if I don't understand correctly but something like this?
UPDATE MYTABLE SET something = table.something
FROM (
SELECT ID, Title ,IDxNumber,
LEAD(IdxNumber,1,0) Over(order by idxnumber)
AS HotCode FROM MYTABLE
) table
WHERE MYTABLE.id = table.id
I have an insert query that goes into a table linked to QuickBooks. The table Test_InvoiceLine has a lot of Part_ID's and Descriptions that are exactly the same.
INSERT INTO InvoiceLine (Part_ID, More_Info )
SELECT Part_ID, Description
FROM Test_InvoiceLine;
How can I write a query that goes into the InvoiceLine table and deletes duplicates with the same Part_ID and Description that are already there?
Use a CTE as a temporary result set. You essentially query for duplicate records that are partitioned by your criteria, and delete the records that are not the first record (keeps the original record).
Double-check me before you blow anything away, because it has been a while since I've done this, but this should work.
WITH CTE AS(
SELECT Part_ID, Description,
RowNum = ROW_NUMBER()OVER(PARTITION BY Part_ID, Description ORDER BY Part_ID, Description)
FROM Test_InvoiceLine
)
DELETE FROM CTE WHERE RowNum > 1
Source: How to delete duplicate records in SQL Server
Is there a reason why you need to do an insert then delete? If you're trying to insert -> delete, it sounds like you're actually trying to update the data by Part_ID.
update InvoiceLine a
set More_Info = b.Description
from ( select Part_ID,
Description
from Test_InvoiceLine ) b
where b.Part_ID = a.Part_ID
This will update More_Info in the InvoiceLine table with Description.
This is SQL Server, however, ROW_NUMBER is widely used in other RDMS.
Here is the query you need.
;WITH Data AS
(
SELECT
Part_ID,Description,
RowNumber = ROW_NUMBER() OVER(PARTITION BY Part_Id,Description ORDER BY Part_Id,Description)
FROM Test_InvoiceLine
)
DELETE FROM Data WHERE RowNumber > 1
I don't know how More_Info will make a difference here as the duplicate key does not include it, according to your post, however, if you need to inspect the more_info values in the delete statement then perhaps you could use something similar to the query below.
;WITH Data AS
(
SELECT
More_Info,
Part_ID,Description,
RowNumber = ROW_NUMBER() OVER(PARTITION BY Part_Id,Description ORDER BY Part_Id,Description)
FROM Test_InvoiceLine
)
DELETE T
FROM Test_InvoiceLine T
INNER JOIN Data D ON D.RowNumber > 1 AND D.MoreInfo = "Y" AND D.Part_Id = T.Part_ID
I needed an advice regarding a SQL statement that has to run with DB2 and Oracle.
Some time ago a database table has been set up without an ID column. Adding the ID column is not the problem but I absolutely need to fill it with the row number of each row.
I found out, that rank() would be perfect but here I'm not able to select for specific values because then I always get the value '1'.
When I set up an intermediate table as described below, I output all data, that I need
WITH MY_TEMP_TABLE AS
(
SELECT RANK() OVER (ORDER BY CODE ASC) MY_ROW, CODE, LAND
FROM SECOND_TABLE
)
SELECT *
FROM SECOND_TABLE
INNER JOIN MY_TEMP_TABLE ON SECOND_TABLE.CODE=MY_TEMP_TABLE.CODE
How is it possible to update the ID column in the database table (here: SECOND_TABLE) with the values in MY_ROW?
Thanks a lot...
Use row_number() instead of rank():
WITH MY_TEMP_TABLE AS
(
SELECT row_number() OVER (ORDER BY CODE ASC) MY_ROW, CODE, LAND
FROM SECOND_TABLE
)
SELECT *
FROM SECOND_TABLE
INNER JOIN MY_TEMP_TABLE ON SECOND_TABLE.CODE=MY_TEMP_TABLE.CODE
I am cleaning out a database table without a primary key (I know, I know, what were they thinking?). I cannot add a primary key, because there is a duplicate in the column that would become the key. The duplicate value comes from one of two rows that are in all respects identical. I can't delete the row via a GUI (in this case MySQL Workbench, but I'm looking for a database agnostic approach) because it refuses to perform tasks on tables without primary keys (or at least a UQ NN column), and I cannot add a primary key, because there is a duplicate in the column that would become the key. The duplicate value comes from one...
How can I delete one of the twins?
SET ROWCOUNT 1
DELETE FROM [table] WHERE ....
SET ROWCOUNT 0
This will only delete one of the two identical rows
One option to solve your problem is to create a new table with the same schema, and then do:
INSERT INTO new_table (SELECT DISTINCT * FROM old_table)
and then just rename the tables.
You will of course need approximately the same amount of space as your table requires spare on your disk to do this!
It's not efficient, but it's incredibly simple.
Note that MySQL has its own extension of DELETE, which is DELETE ... LIMIT, which works in the usual way you'd expect from LIMIT: http://dev.mysql.com/doc/refman/5.0/en/delete.html
The MySQL-specific LIMIT row_count option to DELETE tells the server
the maximum number of rows to be deleted before control is returned to
the client. This can be used to ensure that a given DELETE statement
does not take too much time. You can simply repeat the DELETE
statement until the number of affected rows is less than the LIMIT
value.
Therefore, you could use DELETE FROM some_table WHERE x="y" AND foo="bar" LIMIT 1; note that there isn't a simple way to say "delete everything except one" - just keep checking whether you still have row duplicates.
delete top(1) works on Microsoft SQL Server (T-SQL).
This can be accomplished using a CTE and the ROW_NUMBER() function, as below:
/* Sample Data */
CREATE TABLE #dupes (ID INT, DWCreated DATETIME2(3))
INSERT INTO #dupes (ID, DWCreated) SELECT 1, '2015-08-03 01:02:03.456'
INSERT INTO #dupes (ID, DWCreated) SELECT 2, '2014-08-03 01:02:03.456'
INSERT INTO #dupes (ID, DWCreated) SELECT 1, '2013-08-03 01:02:03.456'
/* Check sample data - returns three rows, with two rows for ID#1 */
SELECT * FROM #dupes
/* CTE to give each row that shares an ID a unique number */
;WITH toDelete AS
(
SELECT ID, ROW_NUMBER() OVER (PARTITION BY ID ORDER BY DWCreated) AS RN
FROM #dupes
)
/* Delete any row that is not the first instance of an ID */
DELETE FROM toDelete WHERE RN > 1
/* Check the results: ID is now unique */
SELECT * FROM #dupes
/* Clean up */
DROP TABLE #dupes
Having a column to ORDER BY is handy, but not necessary unless you have a preference for which of the rows to delete. This will also handle all instances of duplicate records, rather than forcing you to delete one row at a time.
For PostgreSQL you can do this:
DELETE FROM tablename
WHERE id IN (SELECT id
FROM (SELECT id, ROW_NUMBER()
OVER (partition BY column1, column2, column3 ORDER BY id) AS rnum
FROM tablename) t
WHERE t.rnum > 1);
column1, column2, column3 would the column set which have duplicate values.
Reference here.
This works for PostgreSQL
DELETE FROM tablename WHERE id = 123 AND ctid IN (SELECT ctid FROM tablename WHERE id = 123 LIMIT 1)
Tried LIMIT 1? This will only delete 1 of the rows that match your DELETE query
DELETE FROM `table_name` WHERE `column_name`='value' LIMIT 1;
In my case I could get the GUI to give me a string of values of the row in question (alternatively, I could have done this by hand). On the suggestion of a colleague, in whose debt I remain, I used this to create an INSERT statement:
INSERT
'ID1219243408800307444663', '2004-01-20 10:20:55', 'INFORMATION', 'admin' (...)
INTO some_table;
I tested the insert statement, so that I now had triplets. Finally, I ran a simple DELETE to remove all of them...
DELETE FROM some_table WHERE logid = 'ID1219243408800307444663';
followed by the INSERT one more time, leaving me with a single row, and the bright possibilities of a primary key.
in case you can add a column like
ALTER TABLE yourtable ADD IDCOLUMN bigint NOT NULL IDENTITY (1, 1)
do so.
then count rows grouping by your problem column where count >1 , this will identify your twins (or triplets or whatever).
then select your problem column where its content equals the identified content of above and check the IDs in IDCOLUMN.
delete from your table where IDCOLUMN equals one of those IDs.
You could use a max, which was relevant in my case.
DELETE FROM [table] where id in
(select max(id) from [table] group by id, col2, col3 having count(id) > 1)
Be sure to test your results first and having a limiting condition in your "having" clausule. With such a huge delete query you might want to update your database first.
delete top(1) tableNAme
where --your conditions for filtering identical rows
I added a Guid column to the table and set it to generate a new id for each row. Then I could delete the rows using a GUI.
In PostgreSQL there is an implicit column called ctid. See the wiki. So you are free to use the following:
WITH cte1 as(
SELECT unique_column, max( ctid ) as max_ctid
FROM table_1
GROUP BY unique_column
HAVING count(*) > 1
), cte2 as(
SELECT t.ctid as target_ctid
FROM table_1 t
JOIN cte1 USING( unique_column )
WHERE t.ctid != max_ctid
)
DELETE FROM table_1
WHERE ctid IN( SELECT target_ctid FROM cte2 )
I'm not sure how safe it is to use this when there is a possibility of concurrent updates. So one may find it sensible to make a LOCK TABLE table_1 IN ACCESS EXCLUSIVE MODE; before actually doing the cleanup.
In case there are multiple duplicate rows to delete and all fields are identical, no different id, the table has no primary key , one option is to save the duplicate rows with distinct in a new table, delete all duplicate rows and insert the rows back. This is helpful if the table is really big and the number of duplicate rows is small.
--- col1 , col2 ... coln are the table columns that are relevant.
--- if not sure add all columns of the table in the select bellow and the where clause later.
--- make a copy of the table T to be sure you can rollback anytime , if possible
--- check the ##rowcount to be sure it's what you want
--- use transactions and rollback in case there is an error
--- first find all with duplicate rows that are identical , this statement could be joined
--- with the first one if you choose all columns
select col1,col2, --- other columns as needed
count(*) c into temp_duplicate group by col1,col2 having count(*) > 1
--- save all the rows that are identical only once ( DISTINCT )
insert distinct * into temp_insert from T , temp_duplicate D where
T.col1 = D.col1 and
T.col2 = D.col2 --- and other columns if needed
--- delete all the rows that are duplicate
delete T from T , temp_duplicate D where
T.col1 = D.col1 and
T.col2 = D.col2 ---- and other columns if needed
--- add the duplicate rows , now only once
insert into T select * from temp_insert
--- drop the temp tables after you check all is ok
If, like me, you don't want to have to list out all the columns of the database, you can convert each row to JSONB and compare by that.
(NOTE: This is incredibly inefficient - be careful!)
select to_jsonb(a.*), to_jsonb(b.*)
FROM
table a
left join table b
on
a.entry_date < b.entry_date
where (SELECT NOT exists(
SELECT
FROM jsonb_each_text(to_jsonb(a.*) - 'unwanted_column') t1
FULL OUTER JOIN jsonb_each_text(to_jsonb(b.*) - 'unwanted_column') t2 USING (key)
WHERE t1.value<>t2.value OR t1.key IS NULL OR t2.key IS NULL
))
Suppose we want to delete duplicate records with keeping only 1 unique records from Employee table - Employee(id,name,age)
delete from Employee
where id not in (select MAX(id)
from Employee
group by (id,name,age)
);
You can use limit 1
This works perfectly for me with MySQL
delete from `your_table` [where condition] limit 1;
DELETE FROM Table_Name
WHERE ID NOT IN
(
SELECT MAX(ID) AS MaxRecordID
FROM Table_Name
GROUP BY [FirstName],
[LastName],
[Country]
);
I want to know the way we can remove duplicate records where PK is uniqueidentifier.
I have to delete records on the basis of duplicate values in a set of fields.we can use option to get temptable using Row_Number() and except row number one we can delete rest or the records.
But I wanted to build one liner query. Any suggestion?
You can use CTE to do this, without seeing your table structure here is the basic SQL
;with cte as
(
select *, row_number() over(partition by yourfields order by yourfields) rn
from yourTable
)
delete
from cte
where rn > 1
delete from table t using table ta where ta.dup_field=t.dup_field and t.pk >ta.pk
;