Can you help me with sql query to get the desired result
Database used :- Redshift
requirement is
I have 3 columns as:- dish_id,cateogory_id,counter
So i want counter to increase +1 if the dish_id is repeated and if not it should remain 1
the query i need should be able to query the source table and get the results as
dish_id category_id counter
21 4 1
21 6 2
21 6 3
12 1 1
Unless I missunderstood your question, you can accomplish that using window functions:
SELECT *,row_number() OVER (PARTITION BY dish_id) FROM my_table;
Related
I would like select some elements from the last id
Here an example that I have :
id money
1 200
1 150
1 500
3 50
4 40
4 300
5 110
Here what I would like :
1 500
3 50
4 300
5 110
So like you can see, I took last id and the money who corresponds.
I tried to do a group by id order by id descending with limit 1. But limit 1 is not available in proc sql from sas and it doesn't work.
Thanks in advance
Unlike SAS datasets, SQL tables represent unordered sets. In your case, it looks like you want the maximum value in the second column, in which case you can use aggregation:
proc sql;
select id, max(money)
from t
group by id;
If you actually mean the last row per id based on the ordering in the SAS dataset, I would suggest using a data step instead.
I have a project where I am taking Documents from one system and importing them into another.
The first system has the documents and associated keywords stored. I have a query that will return the results which will then be used as the index file to import them into the new system. There are about 1.8 million documents involved so this means 1.8 million rows (One per document).
I need to divide the returned results into blocks of 40,000 to make importing them in batches of 40,000 at a time, rather than one long import.
I have the query to return the results I need. Just need to know how to take that and break it up for easier import. My apologies if I have included to little information. This is my first time here asking for help.
Use the built-in function ORA_HASH to divide the rows into 45 buckets of roughly the same number of rows. For example:
select * from some_table where ora_hash(id, 44) = 0;
select * from some_table where ora_hash(id, 44) = 1;
...
select * from some_table where ora_hash(id, 44) = 44;
The function is deterministic and will always return the same result for the same input. The resulting number starts with 0 - which is normal for a hash, but unusual for Oracle, so the query may look off-by-one at first. The hash works better with more distinct values, so pass in the primary key or another unique value if possible. Don't use a low-cardinality column, like a status column, or the buckets will be lopsided.
This process is in some ways inefficient, since you're re-reading the same table 45 times. But since you're dealing with documents, I assume the table scanning won't be the bottleneck here.
A prefered way to bucketing the ID is to use the NTILE analytic function.
I'll demonstrate this on a simplified example with a table with 18 rows that should be divided in four chunks.
select listagg(id,',') within group (order by id) from tab;
1,2,3,7,8,9,10,15,16,17,18,19,20,21,23,24,25,26
Note, that the IDs are not consecutive, so no arithmetic can be used - the NTILE gets the parameter of the requested number of buckets (4) and calculates the chunk_id
select id,
ntile(4) over (order by ID) as chunk_id
from tab
order by id;
ID CHUNK_ID
---------- ----------
1 1
2 1
3 1
7 1
8 1
9 2
10 2
15 2
16 2
17 2
18 3
19 3
20 3
21 3
23 4
24 4
25 4
26 4
18 rows selected.
All but the last bucket are of the same size, the last one can be smaller.
If you want to calculate the ranges - use simple aggregation
with chunk as (
select id,
ntile(4) over (order by ID) as chunk_id
from tab)
select chunk_id, min(id) ID_from, max(id) id_to
from chunk
group by chunk_id
order by 1;
CHUNK_ID ID_FROM ID_TO
---------- ---------- ----------
1 1 8
2 9 17
3 18 21
4 23 26
I want to select each 5 rows to be unique and the select pattern applies for the rest of the result (i.e if the result contains 10 records I am expecting to have 2 set of 5 unique rows)
Example:
What I have:
1
1
5
3
4
5
2
4
2
3
Result I want to achieve:
1
2
3
4
5
1
2
3
4
5
I have tried and searched a lot but couldn't find anything close to what I want to achieve.
Assuming that you can somehow order the rows within the sets of 5:
SELECT t.Row % 5, t.Row FROM #T t
ORDER BY t.Row , t.Row % 5
We could probably get closer to the truth with more details about what your data looks like and what it is you're trying to actually do.
This will work with the sample of data you provided
SELECT DISTINCT(thevalue) FROM theresults
UNION ALL
SELECT DISTINCT(thevalue) FROM theresults
But it's unclear to me if it's really what you need.
For instance :
if your table/results returns 12 rows, do you still want 2x5 rows or do you want 2x6 rows ?
do you have always in your table/results the same rows in double ?
There's a lot more questions to rise and no hint about them in what you asked.
I have 2 procedures (say A and B). They both return data with similar columns set (Id, Name, Count). To be more concrete, procedures results examples are listed below:
A:
Id Name Count
1 A 10
2 B 11
B:
Id Name Count
1 E 14
2 F 15
3 G 16
4 H 17
The IDs are generated as ROW_NUMBER() as I don't have own identifiers for these records because they are aggregated values.
In code I query over the both results using the same class NameAndCountView.
And finally my problem. When I look into results after executing both procedures sequentially I get the following:
A:
Id Name Count
1 A 10 ->|
2 B 11 ->|
|
B: |
Id Name Count |
1 A 10 <-|
2 B 11 <-|
3 G 16
4 H 17
As you can see results in the second set are replaced with results with the same IDs from the first. Of course the problem take place because I use the same class for retrieving data, right?
The question is how to make this work without creating additional NameAndCountView2-like class?
If possible, and if you don't really mind about the original Id values, maybe you can try having the first query return even Ids :
ROW_NUMBER() over (order by .... )*2
while the second returns odd Ids :
ROW_NUMBER() over (order by .... )*2+1
This would also allow you to know where the Ids come from.
I guess this would be repeatable with N queries by having the query number i selecting
ROW_NUMBER() over (order by .... )*n+i
Hope this will help
please tell me how to write this query
i have an access table
number
2
2
1
2
2
1
1
3
2
i want a query that gives
number count
2 5
1 3
3 1
any help appreciated
something like...
SELECT number, count(number) AS count
FROM table
GROUP BY number
It's a bad idea to have a column named number since it is a reserved keyword.
You probably want something like
select number_, count(*) as count from ... group by number_