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I have a problem with an order by sql server, I need to sort the records in the Ejey field, as follows:
Alta/Deficiente
Baja/Optima
Deficiente/Deficiente
Media/Alta
Optima/Deficiente
.... So Suspensively
As shown by the selected records in gray, I clarify that my table of the image has 625 records and the other fields must remain the same.
As far as each value of EjeY has the same count of rows (5) one idea is to order the rows by the modulo of its row's row number with this count.
This could work:
--Save your data in a temp table ordered by the value of EjeY column
SELECT *
INTO #TEMP2
FROM
(
SELECT *
FROM YouTable
) AS TEMP1
ORDER BY TEMP1.EjeY --Here you modify the ordering mode you want every time your EjeY values to be displayed
--For each row of the temp table calculate the module the row number
--with the count of rows per EjeY value
--(that must be 5 in your situation)
--and order the table by this value and then by row number)
SELECT
row_col%(select top 1 count(EjeY) from YouTable group by EjeY) AS mod_col,
row_col,
TEMP3.* --your columns
FROM
(SELECT *,
ROW_NUMBER() OVER (ORDER BY (SELECT null))-1 as row_col
FROM #TEMP2) as TEMP3
ORDER BY mod_col,TEMP3.row_col
Related
I would like to get a new ID, no matter the format (in the example below 11,12,13...)
Based on the following condition:
Every time the days column value is greater then 1 and not null then current row and all following ones will get the same ID until a new value will meet the condition.
Within the same email
Below you can see the expected 1 (in the format of XX)
I thought about using two conditions with the following order between them
Every time the days column value is greater then 1 then all following rows will get the same ID until a new value will meet the condition.
2.AND When lag (previous) is equal to 0/1/null.
Assuming you have an EmailDate column over which you're ordering (a DATETIME field, really), try something like this:
WITH
TableNameWithEmailDateIDs AS (
SELECT
*,
ROW_NUMBER() OVER (
ORDER BY
Email DESC,
EmailDate
) AS EmailDateID
FROM
TableName
),
IDs AS (
SELECT
*,
LEAD(EmailDateID, 1) OVER (
ORDER BY
Email,
EmailDate
) AS LeadEmailDateID
FROM
(
SELECT
*,
-- REMOVE +10 if you don't want 11 to be starting ID
ROW_NUMBER() OVER (
ORDER BY
Email DESC,
EmailDate
)+10 AS ID
FROM
TableNameWithEmailDateIDs
WHERE
Days > 1
OR Days IS NULL
) X
)
SELECT
COALESCE(TableName.EmailDate, IDs.EmailDate) AS EmailDate,
IDs.Email,
COALESCE(TableName.Days, IDs.Days) AS Days,
IDs.ID
FROM
IDs
LEFT JOIN TableNameWithEmailDateIDs TableName
ON IDs.Email = TableName.Email
AND TableName.EmailDateID BETWEEN
IDs.EmailDateID
AND IDs.LeadEmailDateID-1
ORDER BY
ID DESC,
TableName.EmailDate DESC
;
First, create a CTE that generates IDs for each distinct Email/Date combo (helpful for LEFT JOIN condition later). Then, create a CTE that generates IDs for rows that meet your condition (i.e. the important rows). Finally, LEFT JOIN your main table onto that CTE to fill in the "gaps", so to speak.
I suggest running each of the components of this query independently to fully understand what's going on.
Hope it helps!
I have the following code which is taking a looong time to get executed. What I need to do is select the column having row number equals 1 after partitioning it by three columns (col_1, col_2, col_3) [which are also the key columns] and ordering by some columns as mentioned below. The number of records in the table is around 90 million. Am I following the best approach or is there any other better one?
with cte as (SELECT
b.*
,ROW_NUMBER() OVER ( PARTITION BY col_1,col_2,col_3
ORDER BY new_col DESC, new_col_2 DESC, new_col_3 DESC ) AS ROW_NUMBER
FROM (
SELECT
*
,CASE
WHEN update_col = ' ' THEN new_update_col
ELSE update_col
END AS new_col_1
FROM schema_name.table_name
) b
)
select top 10 * from cte WHERE ROW_NUMBER=1
Currently you are applying CASE on different columns which is impacting all rows in the database table. CASE (String Comparison) Is a costly method.
At the end, you are keeping only records with ROW NUMBER = 1. If I guess this filter keeping Half of your all records, this will increase the query execution time if you filter (Generate ROW NUMBER First and Keep Rows with RN=1) first and then apply CASE method on columns.
There is a table with tow columns(ID, Data) and there are 3 rows with same value.
ID Data
4 192.168.0.22
4 192.168.0.22
4 192.168.0.22
Now I want to change third row DATA column. In update SQL Server Generate an error that I ca not change the value.
I can delete all 3 rows. But I can not delete third row separately.
This table is for a software that I bought and I changed the third Server IP.
You can try the following query
create table #tblSimilarValues(id int, ipaddress varchar(20))
insert into #tblSimilarValues values (4, '192.168.0.22'),
(4, '192.168.0.22'),(4, '192.168.0.22')
Use Below query if you want to change all rows
with oldData as (
select *,
count(*) over (partition by id, ipaddress) as cnt
from #tblSimilarValues
)
update oldData
set ipaddress = '192.168.0.22_1'
where cnt > 1;
select * from #tblSimilarValues
Use Below query if you want to skip firs row
;with oldData as (
select *,
ROW_NUMBER () over (partition by id, ipaddress order by id, ipaddress) as cnt
from #tblSimilarValues
)
update oldData
set ipaddress = '192.168.0.22_2'
where cnt > 1;
select * from #tblSimilarValues
drop table #tblSimilarValues
You can find the live demo live demo here
Since there is no column that allows us to distinguish these rows from each other, there's no "third row" (nor a first or second one for that matter).
We can use a ROW_NUMBER function to apply arbitrary row numbers to these rows, however, and if we place that in a CTE, we can apply DELETE/UPDATE actions via the CTE and use the arbitrary row numbers:
declare #t table (ID int not null, Data varchar(15))
insert into #t(ID,Data) values
(4,'192.168.0.22'),
(4,'192.168.0.22'),
(4,'192.168.0.22')
;With ArbitraryAssignments as (
select *,ROW_NUMBER() OVER (PARTITION BY ID, Data ORDER BY Data) as rn
from #t
)
delete from ArbitraryAssignments where rn > 2
select * from #t
This produces two rows of output - one row was deleted.
Note that I say that the ROW_NUMBER is arbitrary. One of the expressions in both the PARTITION BY and ORDER BY clauses is the same. By definition, then, we know that no real ORDER is defined by this (because all rows within the same partition, by definition, have the same value for that expression).
In this case ID columns allows duplicate value which is wrong, ID should be unique.
Now what you can do is create a new column make that unique or Primary Key or change the duplicate values of ID column and make it Unique/Primary key.
Now as per your Unique key/Primary key you can update DATA column value by query as below:
UPDATE <Table Name>
SET DATA = 'new data'
WHERE ID = 3;
I have a table that look like this:
The problem is I need to get the last record with duplicates in the column "NRODENUNCIA".
You can use MAX(DENUNCIAID), along with GROUP BY... HAVING to find the duplicates and select the row with the largest DENUNCIAID:
SELECT MAX(DENUNCIAID), NRODENUNCIA, FECHAEMISION, ADUANA, MES, NOMBREESTADO
FROM YourTable
GROUP BY NRODENUNCIA, FECHAEMISION, ADUANA, MES, NOMBREESTADO
HAVING COUNT(1) > 1
This will only show rows that have at least one duplicate. If you want to see non-duplicate rows too, just remove the HAVING COUNT(1) > 1
There are a number of solutions for your problem. One is to use row_number.
Note that I've ordered by DENUNCIID in the OVER clause. This defines the "Last Record" as the one that has the largest DENUNCIID. If you want to define it differently you'd need to change the field that is being ordered.
with dupes as (
SELECT
ROW_NUMBER() OVER (Partition by NRODENUNCIA ORDER BY DENUNCIID DESC) RN,
*
FROM
YourTable
)
SELECT * FROM dupes where rn = 1
This only get's the last record per dupe.
If you want to only include records that have dupes then you change the where clause to
WHERE rn =1
and NRODENUNCIA in (select NRODENUNCIA from dupes where rn > 1)
Given;
CREATE TABLE T1 (ID INTEGER, DESCRIPTION VARCHAR2(20));
INSERT INTO T1 VALUES (1,'ONE');
INSERT INTO T1 VALUES (2,'TWO');
INSERT INTO T1 VALUES (3,'THREE');
INSERT INTO T1 VALUES (4,'FOUR');
INSERT INTO T1 VALUES (5,'FIVE');
COMMIT;
Why does;
SELECT * FROM
( SELECT ROWNUM, ID, DESCRIPTION
FROM T1)
WHERE MOD(ROWNUM,1)=0;
Return
ROWNUM ID DESCRIPTION
------ -------------------------------------- --------------------
1 1 ONE
2 2 TWO
3 3 THREE
4 4 FOUR
5 5 FIVE
Whereas;
SELECT * FROM
( SELECT ROWNUM, ID, DESCRIPTION
FROM T1)
WHERE MOD(ROWNUM,2)=0;
Return zero rows ???
Confused, expected ROWNUM=(2,4) to be returned...
SELECT B.* FROM
( SELECT ROWNUM a, ID, DESCRIPTION
FROM T1) B
WHERE MOD(A,2)=0;
Reason: Your approach involves running rownum twice. You don't need to; nor really do you want to. Based on order of operations, the where clause will execute before the the outer select; which means the select hasn't determined the values for each row, and the number of rows is not known yet.
Additional:
I would recommend adding an order by to the inline view so the rownumbers are in a expected specific order as opposed to what the engine derives.
You have 2 operations of ROWNUM.
The 1st ROWNUM generates the numbers 1 through 5.
The 2nd ROWNUM doesn't generate anything because for the row the ROWNUM value is 1, but since MOD(1,2)=0 is false, the record is not being outputted and the ROWNUM is not being incremented, failing the condition again and again.
This query, using alias, returns exactly what you have expected:
SELECT * FROM
( SELECT ROWNUM as rn, ID, DESCRIPTION
FROM T1)
WHERE MOD(rn,2)=0;
Some facts about the ROWNUM pseudo column in Oracle:
The ROWNUM assigned to each row is determined by the order in which Oracle retrieves the row from the DB.
The order in which rows are returned is non deterministic, such that running it once may return rows in one ordering, and a second time around may have a different ordering if the base tables have been reorganized, or Oracle uses a different query plan.
The order in which ROWNUMs are assigned to rows is not necessarily correlated with the that of an order by clause (the order by clause may affect the ROWNUM order since it may cause a different query plan to be used, but the ROWNUMbers are unlikely to match the sort order).
ROWNUMbers are assigned after the records are filtered by the WHERE clause, so if you filter out ROWNUM 1 you will never return any records.
Filtering a subquery that returns an aliased ROWNUM column works because the entire subquery is returned to the outer query before the outer query filters the rows, but the ROWNUMs will still have a non deterministic order.
To successfully return a top N or Nth row query in a deterministic fashion you need to assign row numbers in a deterministic way. One such way is to use the the `ROW_NUMBER' analytic function in a subquery:
select * from
(select ROW_NUMBER() over (order by ID) rn
, ID
, DESCRIPTION
from T1)
where rn <= 4 -- Top N
or
where rn = 4 -- 1st Nth row
or even
WHERE MOD(rn,2)=0 -- every Nth row
In either case the ORDER BY clause in the ROW_NUMBER analytic function needs to match the granularity of the data otherwise ties in the ordering will again be non deterministic, most likely matching the current ROWNUM ordering.