I've a query in MySQL and I'm looking for a query which can perform below operation using Posgres
MySQL Query :
update APT_ADHOC_DISH_SRC_TABLE_AAMIR_TCH3 a,
(
SELECT #row_number:=CASE WHEN #email=email THEN #row_number+1 ELSE 1 END AS row_number,
#email:=email AS email,id
FROM APT_ADHOC_DISH_SRC_TABLE_AAMIR_TCH3,
(SELECT #row_number:=0,#email:='') AS t
ORDER BY email
) b
set a.r_no=b.row_number where a.id=b.id
Output:
Email
Row Number
Aamir
1
Aamir
2
Aamir
3
Suresh
1
Suresh
2
Hafiz
1
WITH cte AS (
SELECT id, ROW_NUMBER() OVER (PARTITION BY email ORDER BY id) AS row_number
FROM APT_ADHOC_DISH_SRC_TABLE_AAMIR_TCH3
)
UPDATE APT_ADHOC_DISH_SRC_TABLE_AAMIR_TCH3
SET row_number = cte.row_number
FROM cte
WHERE APT_ADHOC_DISH_SRC_TABLE_AAMIR_TCH3.id = cte.id
https://www.db-fiddle.com/f/3RqNHRGFjkU74v33upyfhi/0
Related
I have a database table which looks like this.
id account_id action time_point
3 234 delete 100
1 656 create 600
1 4435 update 900
3 645 create 50
I need to group this table by id and select particular row where time_point has a largest value.
Result table should look like this:
id account_id action time_point
3 234 delete 100
1 4435 update 900
Thanks for help,
qwew
In Postgres, I would recommend distinct on to solve this top 1 per group problem:
select distinct on (id) *
from mytable
order by id, time_point desc
However, this does not allow possible to ties. If so, rank() is a better solution:
select *
from (
select t.*, rank() over(partition by id order by time_point desc) rn
from mytable t
) t
where rn = 1
Or, if you are running Postgres 13:
select *
from mytable t
order by rank() over(partition by id order by time_point desc)
fetch first row with ties
check this.
select * from x
where exists (
select 1 from x xin
where xin.id = x.id
having max(time_point) = time_point
);
I guess this is a standard problem. But I could not find a proper solution yet.
I have three columns in table A:
ID ID_Version Var
1 1 A
1 2 A
1 3 X
1 4 D
2 1 B
2 2 Z
2 3 D
3 1 A
4 1 B
4 2 Q
4 3 Z
For every unique ID, I would like to isolate the Var-value that belongs to the maximal ID-Version.
For ID = 1 this would be D, for ID = 2 this would be D, for ID = 3 this would be A and for ID = 4 this would be Z.
I tried to use a group by statement but I cannot select Var-values when using the max-function on ID-Version and grouping by ID.
Does anyone have a clue how to write fast, effective code for this simple problem?
use row_number() analytic function :
select ID,Var from
(
select row_number() over (partition by id order by id_version desc) as rn,
t.*
from tab t
)
where rn = 1
or max(var) keep (dense_rank...)
select id, max(var) keep (dense_rank first order by id_version desc) as var
from tab
group by id
Demo
You could use ranking function:
SELECT *
FROM (SELECT tab.*, ROW_NUMBER() OVER(PARTITION BY ID ORDER BY ID_Version DESC) rn
FROM tab)
WHERE rn = 1
Oracle has the keep syntax, so you can also use aggregation:
select id, max(id_version) as id_version,
max(var) keep (dense_rank first order by id_version desc) as var
from a
group by id;
You could also use a simple join to do what you want, see below :
SELECT A.id, A.var FROM A
JOIN
(SELECT id, MAX(id_version) as id_version
FROM A
GROUP BY id) temp ON (temp.id = A.id AND temp.id_version = A.id_version)
Or you could also use a subquery like this :
SELECT a1.id, a1.var FROM A a1
WHERE a1.id_version = (SELECT MAX(id_version) FROM A a2 WHERE a2.id = a1.id)
I'm using SQL Server Management Studio 2012. I have a similar looking output from a query shown below. I want to eliminate someone from the query who has 2 contracts.
Select
Row_Number() over (partition by ID ORDER BY ContractypeDescription DESC) as [Row_Number],
Name,
ContractDescription,
Role
From table
Output
Row_Number ID Name Contract Description Role
1 1234 Mike FullTime Admin
2 1234 Mike Temp Manager
1 5678 Dave FullTime Admin
1 9785 Liz FullTime Admin
What I would like to see
Row_Number ID Name Contract Description Role
1 5678 Dave FullTime Admin
1 9785 Liz FullTime Admin
Is there a function rather than Row_Number that allows you to group rows together so I can then use something like 'where Row_Number not like 1 and 2'?
You can use HAVING as
SELECT ID,
MAX(Name) Name,
MAX(ContractDescription) ContractDescription,
MAX(Role) Role
FROM t
GROUP BY ID
HAVING COUNT(*) = 1;
Demo
Try this:
select * from (
Select
Count(*) over (partition by ID ) as [Row_Number],
Name,
ContractDescription,
Role
From table
)t where [Row_Number] = 1
You can check this option-
SELECT *
FROM table
WHERE ID IN
(
SELECT ID
FROM table
GROUP BY ID
HAVING COUNT(*) = 1
)
You can use a CTE to get all the ids of people who got only one contract and then just join the result of the CTE with your table.
;with cte as (
select
id
,COUNT(id) as no
from #tbl
group by id
having COUNT(id) = 1
)
select
t.id
,t.name
,t.ContractDescription
,t.role
from #tbl t
inner join cte
on t.id = cte.id
Basically you need those record who have exactly one contract.
Just extend your script, (My script is not tested)
;with CTE as
(
Select
Row_Number() over (partition by ID ORDER BY ContractypeDescription DESC) as [Row_Number],
Name,
ContractDescription,
Role
From table
)
select * from CTE c where [Row_Number]=1
and not exists(select 1 from CTE c1 where c.id=c1.id and c1.[Row_Number]>1 )
Is there a function rather than Row_Number that allows you to group
rows together so I can then use something like 'where Row_Number not
like 1 and 2'?
You can use a windowed COUNT(). The key is the OVER() clause.
;WITH WindowedCount AS
(
SELECT
T.*,
WindowCount = COUNT(1) OVER (PARTITION BY T.ID)
FROM
YourTable AS T
)
DELETE W FROM
WindowedCount AS W
WHERE
W.WindowCount > 1
The COUNT() will count the amount of rows for each different ID, so if the same ID appears in 2 or more rows, those rows will be deleted.
I have a SQL table Customer with the following columns:
Customer_ID, Actioncode
I have another table with 1000+ actioncodes. Now I want to update the records in the Customer table with a unique code from the actioncode table.
I use this select statement at the moment:
update t
set t.actiecode = (select top 1 actiecode from data_mgl_campagnemails_codes)
from data_mgl_campagnemails_transfer t;
The result is that all records are updated with the same actiecode. The top 1 is responsible for that. When I remove that I got an error:
Subquery returned more than 1 value
This seems logical. How can I do this without using a cursor?
There is no relationship between the Customer and Code table.
Table structure:
data_mgl_campagnemails_transfer
id customer_id actioncode actioncode_id
1 1 - -
2 3 - -
3 4 - -
data_mgl_campagnemails_codes
id actioncode active
1 TTTT
2 RRRR
3 VVVV
4 RRRW
The result should be:
data_mgl_campagnemails_transfer
id customer_id actioncode actioncode_id
1 1 TTTT 1
2 3 RRRR 2
3 4 VVVV 3
data_mgl_campagnemails_codes
id actioncode active
1 TTTT YES
2 RRRR YES
3 VVVV YES
4 RRRW
This can be a bit tricky using a single statement, because SQL Server likes to optimize things. So the obvious:
update t
set t.actiecode = (select top 1 actiecode
from data_mgl_campagnemails_codes
order by newid()
)
from data_mgl_campagnemails_transfer t;
Also doesn't work. One method is to enumerate things and use a join or correlated subquery:
with t as (
select t.*, row_number() over (order by newid()) as seqnum
from data_mgl_campagnemails_transfer t
),
a as (
select a.*, row_number() over (order by newid()) as seqnum
from data_mgl_campagnemails_codes a
)
update t
set t.actiecode = (select top 1 actiecode from a)
from t join
a
on t.seqnum = a.seqnum;
Another way is to "trick" SQL Server into running the correlated subquery more than once. I think something like this:
update t
set t.actiecode = (select top 1 actiecode
from data_mgl_campagnemails_codes
where t.CustomerId is not null -- references the outer table but really does nothing
order by newid()
)
from data_mgl_campagnemails_transfer t;
I have a table that can have multiple records for ip_address. However, I want to return rows where canceled=0 if multiple records of ip_address exist, otherwise get the first row where canceled=1
id ip_address username canceled
0 10.10.10.1 john 0
1 10.10.10.1 johnny 1
2 10.10.10.1 quincy 1
3 10.10.10.2 bob 1
4 10.10.10.3 kristin 0
Examples returned resultset for SELECT ip_address,username ....:
10.10.10.1 john
10.10.10.2 bob
10.10.10.3 kristin
Using SQLAlchemy/Sqlite if that is of any relevance.
SELECT
b.id,
a.ip_address,
b.username,
b.canceled
FROM (
select distinct(ip_address) from mytable order by canceled) a,
mytable b
WHERE
b.ip_address=a.ip_address;
But that is returning multiple definitions for "ip_address"
The proper query appears to be:
SELECT b.id,a.ip_address,b.username,b.canceled FROM (select distinct(ip_address) from mytable order by canceled) a, mytable b WHERE b.ip_address=a.ip_address GROUP BY b.ip_address
Assuming canceled is an int,this should work.
select *from #temp order by canceled
with cte as
(
select ip_address,username,canceled,ROW_NUMBER() over(partition by ip_address order by canceled) as rn from #temp
)
select *from cte where rn=1