Not exist is not working.
I have a query which is fetching 10k rows... now there are 237 rows which I do not want to be retrieved in my final result but when I am using not exist it is fetching the same no. of rows that is 10k I have used the following query:
Select bu_name,
person_num,
name,
f_config_id,
ass_the
from x_asig_table
where not exist ((select 1
from
(select XXH.x_asig_table.*,
count(*) over (partition by bu_name, person_num, name) as c
from XXH.x_asig_table) t
where c > 1);
The sub-query is not correlated with the main query, i.e. it doesn't matter what row you look at in the main query, the subquery will always give you the same result. So either you get all rows or none. It is not possible with this query to get some rows and others not.
Add criteria to your subquery that relates it to the main query to solve the problem.
You need to connect back to the outer query. Something like this (also simplified your query, untested, but should work):
Select bu_name,
person_num,
name,
f_config_id,
ass_the
from x_asig_table X
where not exist (
SELECT NULL
FROM x_asig_table Y
GROUP BY bu_name,person_num, name
WHERE X.bu_name = Y.bu_name
AND X.person_num = Y.person_num
AND X.name = Y.name
HAVING COUNT(1) > 1
)
You appear to be trying to find only those rows where there is a single row per combination of bu_name, person_num and name (although the question is rather unclear what your intents are). If so, then you can do it without using EXISTS like this:
SELECT bu_name,
person_num,
name,
f_config_id,
ass_the
FROM (
SELECT bu_name,
person_num,
name,
f_config_id,
ass_the,
COUNT(1) OVER ( PARTITION BY bu_name, person_num, name ) AS cnt
FROM x_asig_table
)
WHERE cnt = 1;
Related
I have read in various websites about the count() function but I still cannot make this work.
I made a small table with (id, name, last name, age) and I need to retrieve all columns plus a new one. In this new column I want to display how many times a name shows up or repeats itself in the table.
I have made test and can retrieve but only COLUMN NAME with the count column, but I haven't been able to retrieve all data from the table.
Currently I have this
select a.n_showsup, p.*
from [test1].[dbo].[person] p,
(select count(*) n_showsup
from [test1].[dbo].[person])a
This gives me all data on output but on the column n_showsup it gives me just the number of rows, now I know this is because I'm missing a GROUP BY but then when I write group by NAME it shows me a lot of records. This is an example of what I need:
You can use window functions, if you RDBMS supports them:
select t.*, count(*) over(partition by name) n_showsup
from mytable t
Alternatively, you can join the table with an aggregation query that counts the number of occurences of each name:
select t.*, x.n_showsup
from mytable t
inner join (select name, count(*) n_showsup from mytable group by name) x
on x.name = t.name
While the window function approach (#GMB's answer) is the right way to go, thinking through this from a subquery approach (like you were headed towards) would look something like:
select p.*, a.n_showsup
from [test1].[dbo].[person] p
INNER JOIN (
select name, count(*) n_showsup
from [test1].[dbo].[person]
GROUP BY name
) a ON p.name = a.name
This is VERY close to what you had, the difference is that we are grouping that subquery by name (so we get a count by name) and we can use that in the join criteria which we do with the ON clause on that INNER JOIN.
You should really never ever use a comma in your FROM clause. Instead use a JOIN.
The following query returns the results that I need but I have to add the ID of the row to then update it. If I add the ID directly in the select statement it will return me more results then I need because each ID is unique so the DISTINCT statement see the line as unique.
SELECT DISTINCT ucpse.MemberID, ucpse.ProductID, ucpse.UserID
FROM UserCustomerProductSalaryExceptions as ucpse
WHERE EXISTS (SELECT NULL
FROM UserCustomerProductSalaryExceptions as upcse2
WHERE ucpse.userid = upcse2.userid AND ucpse.MemberID = upcse2.MemberID AND ucpse.ProductID = upcse2.ProductID
GROUP BY upcse2.UserID, upcse2.memberid, upcse2.productid
HAVING COUNT(UserID) >= 2
)
So basically I need to add ucpse.ID in the Select statement while keeping DISTINCT values for MemberID,ProductID and UserID.
Any Ideas ?
Thank you
According to you comment:
If the data has been duplicated 67 times for a given employee with a given product and a given client, I need to keep only one of thoses records. It's not important which one, so this is why I use DISTINC to obtain unique combinaison of given employee with a given product and a given client.
You can use MIN() or MAX() and GROUP BY instead of DISTINCT
SELECT MAX(ucpse.ID) AS ID, ucpse.MemberID, ucpse.ProductID, ucpse.UserID
FROM UserCustomerProductSalaryExceptions as ucpse
WHERE EXISTS (SELECT NULL
FROM UserCustomerProductSalaryExceptions as upcse2
WHERE ucpse.userid = upcse2.userid AND ucpse.MemberID = upcse2.MemberID AND ucpse.ProductID = upcse2.ProductID
GROUP BY upcse2.UserID, upcse2.memberid, upcse2.productid
HAVING COUNT(UserID) >= 2
)
GROUP BY ucpse.MemberID, ucpse.ProductID, ucpse.UserID
UPDATE:
From you comments I think the below query is what you need
DELETE FROM UserCustomerProductSalaryExceptions
WHERE ID NOT IN ( SELECT MAX(ucpse.ID) AS ID
FROM #UserCustomerProductSalaryExceptions
GROUP BY ucpse.MemberID, ucpse.ProductID, ucpse.UserID
HAVING COUNT(ucpse.ID) >= 2
)
If all you want is to delete the duplicates, this will do it:
WITH X AS
(SELECT ID,
ROW_NUMBER() OVER (PARTITION BY MemberID, ProductID, UserID ORDER BY ID) AS DupRowNum<br
FROM UserCustomerProductSalaryExceptions
)
DELETE X WHERE DupRowNum > 1
ID's not necessary - try:
UPDATE uu SET
<your settings here>
FROM UserCustomerProductSalaryExceptions uu
JOIN ( <paste your entire query above here>
) uc ON uc.MemberID=uu.MemberId AND uc.ProductID=uu.ProductId AND uc.UserID=uu.UserId
From the sound of your data structure (which I would STRONGLY advise normalizing as soon as possible), it sounds like you should be updating all the records. It sounds as if each duplicate is important because it contains some information about an employee's relation to a customer or product.
I would probably update all the records. Try this:
UPDATE UCPSE
SET
--Do your updates here
FROM UserCustomerProductSalaryExceptions as ucpse
JOIN
(
SELECT UserID, MemberID, ProductID
FROM UserCustomerProductSalaryExceptions
GROUP BY UserID, MemberID, ProductID
HAVING COUNT(UserID) >= 2
) T
ON ucpse.UserID = T.UserID AND ucpse.MemberID = T.MemberID AND ucpse.ProductID = T.ProductID
EDITED:
I have this query wherein I want to SELECT the first instance of a record from the table petTable.
SELECT id,
pet_ID,
FIRST(petName),
First(Description)
FROM petTable
GROUP BY pet_ID;
The problem is I have huge number of records and this query is too slow. I discovered that GROUP BY slows down the query. Do you have any idea that could make this query faster? or better, a query wherein I don't need to use GROUP BY?
"The problem is I have huge number of records and this query is too slow. I discovered that GROUP BY slows down the query. Do you have any idea that could make this query faster?"
And an index on pet_ID, then create and test this query:
SELECT pet_ID, Min(id) AS MinOfid
FROM petTable
GROUP BY pet_ID;
Once you have that query working, you can join it back to the original table --- then it will select only the original rows which match based on id and you can retrieve the other fields you want from those matching rows.
SELECT pt.id, pt.pet_ID, pt.petName, pt.Description
FROM
petTable AS pt
INNER JOIN
(
SELECT pet_ID, Min(id) AS MinOfid
FROM petTable
GROUP BY pet_ID
) AS sub
ON pt.id = sub.MinOfid;
Your Query could change as,
SELECT ID, pet_ID, petName, Description
FROM petTable
WHERE ID IN
(SELECT Min(ID) As MinID FROM petTable GROUP BY pet_ID);
Or use the TOP clause,
SELECT petTable.petID, petTable.petName, petTable.[description]
FROM petTable
WHERE petTable.ID IN
(SELECT TOP 1 ID
FROM petTable AS tmpTbl
WHERE tmpTbl.petID = petTable.petID
ORDER BY tmpTbl.petID DESC)
ORDER BY petTable.petID, petTable.petName, petTable.[description];
How can one filter a grouped resultset for only those groups that meet some criterion compared against the other groups? For example, only those groups that have the maximum number of constituent records?
I had thought that a subquery as follows should do the trick:
SELECT * FROM (
SELECT *, COUNT(*) AS Records
FROM T
GROUP BY X
) t HAVING Records = MAX(Records);
However the addition of the final HAVING clause results in an empty recordset... what's going on?
In MySQL (Which I assume you are using since you have posted SELECT *, COUNT(*) FROM T GROUP BY X Which would fail in all RDBMS that I know of). You can use:
SELECT T.*
FROM T
INNER JOIN
( SELECT X, COUNT(*) AS Records
FROM T
GROUP BY X
ORDER BY Records DESC
LIMIT 1
) T2
ON T2.X = T.X
This has been tested in MySQL and removes the implicit grouping/aggregation.
If you can use windowed functions and one of TOP/LIMIT with Ties or Common Table expressions it becomes even shorter:
Windowed function + CTE: (MS SQL-Server & PostgreSQL Tested)
WITH CTE AS
( SELECT *, COUNT(*) OVER(PARTITION BY X) AS Records
FROM T
)
SELECT *
FROM CTE
WHERE Records = (SELECT MAX(Records) FROM CTE)
Windowed Function with TOP (MS SQL-Server Tested)
SELECT TOP 1 WITH TIES *
FROM ( SELECT *, COUNT(*) OVER(PARTITION BY X) [Records]
FROM T
)
ORDER BY Records DESC
Lastly, I have never used oracle so apolgies for not adding a solution that works on oracle...
EDIT
My Solution for MySQL did not take into account ties, and my suggestion for a solution to this kind of steps on the toes of what you have said you want to avoid (duplicate subqueries) so I am not sure I can help after all, however just in case it is preferable here is a version that will work as required on your fiddle:
SELECT T.*
FROM T
INNER JOIN
( SELECT X
FROM T
GROUP BY X
HAVING COUNT(*) =
( SELECT COUNT(*) AS Records
FROM T
GROUP BY X
ORDER BY Records DESC
LIMIT 1
)
) T2
ON T2.X = T.X
For the exact question you give, one way to look at it is that you want the group of records where there is no other group that has more records. So if you say
SELECT taxid, COUNT(*) as howMany
GROUP by taxid
You get all counties and their counts
Then you can treat that expressions as a table by making it a subquery, and give it an alias. Below I assign two "copies" of the query the names X and Y and ask for taxids that don't have any more in one table. If there are two with the same number I'd get two or more. Different databases have proprietary syntax, notably TOP and LIMIT, that make this kind of query simpler, easier to understand.
SELECT taxid FROM
(select taxid, count(*) as HowMany from flats
GROUP by taxid) as X
WHERE NOT EXISTS
(
SELECT * from
(
SELECT taxid, count(*) as HowMany FROM
flats
GROUP by taxid
) AS Y
WHERE Y.howmany > X.howmany
)
Try this:
SELECT * FROM (
SELECT *, MAX(Records) as max_records FROM (
SELECT *, COUNT(*) AS Records
FROM T
GROUP BY X
) t
) WHERE Records = max_records
I'm sorry that I can't test the validity of this query right now.
I'm not sure if this is even a good question or not.
I have a complex query with lot's of unions that searches multiple tables for a certain keyword (user input). All tables in which there is searched are related to the table book.
There is paging on the resultset using LIMIT, so there's always a maximum of 10 results that get withdrawn.
I want an extra column in the resultset displaying the total amount of results found however. I do not want to do this using a separate query. Is it possible to add a count() column to the resultset that counts every result found?
the output would look like this:
ID Title Author Count(...)
1 book_1 auth_1 23
2 book_2 auth_2 23
4 book_4 auth_.. 23
...
Thanks!
This won't add the count to each row, but one way to get the total count without running a second query is to run your first query using the SQL_CALC_FOUND_ROWS option and then select FOUND_ROWS(). This is sometimes useful if you want to know how many total results there are so you can calculate the page count.
Example:
select SQL_CALC_FOUND_ROWS ID, Title, Author
from yourtable
limit 0, 10;
SELECT FOUND_ROWS();
From the manual:
http://dev.mysql.com/doc/refman/5.1/en/information-functions.html#function_found-rows
The usual way of counting in a query is to group on the fields that are returned:
select ID, Title, Author, count(*) as Cnt
from ...
group by ID, Title, Author
order by Title
limit 1, 10
The Cnt column will contain the number of records in each group, i.e. for each title.
Regarding second query:
select tbl.id, tbl.title, tbl.author, x.cnt
from tbl
cross join (select count(*) as cnt from tbl) as x
If you will not join to other table(s):
select tbl.id, tbl.title, tbl.author, x.cnt
from tbl, (select count(*) as cnt from tbl) as x
My Solution:
SELECT COUNT(1) over(partition BY text) totalRecordNumber
FROM (SELECT 'a' text, id_consult_req
FROM consult_req cr);
If your problem is simply the speed/cost of doing a second (complex) query I would suggest you simply select the resultset into a hash-table and then count the rows from there while returning, or even more efficiently use the rowcount of the previous resultset, then you do not even have to recount
This will add the total count on each row:
select count(*) over (order by (select 1)) as Cnt,*
from yourtable
Here is your answare:
SELECT *, #cnt count_rows FROM (
SELECT *, (#cnt := #cnt + 1) row_number FROM your_table
CROSS JOIN (SELECT #cnt := 0 AS variable) t
) t;
You simply cannot do this, you'll have to use a second query.