I've got two tables wchich I need to join with Select and I've got a problem.
The tables look like that:
table_price
Product_ID | Buy_date | Buy_price |
1 | 16.10.01 | 2.50 |
1 | 16.11.02 | 3.20 |
2 | 16.10.31 | 3.80 |
table expire_date
Product_ID | Count | Exp_date |
1 | 1000 | 17.10.01|
1 | 500 | 17.11.31|
2 | 500 | 17.11.01|
I need to write a select in Oracle PL/SQL wchich gives me following results:
Product_ID| Count | Exp_date| last_buy_price|
1 | 1000 | 17.10.01| 3.20 |
1 | 500 | 17.31.31| 3.20 |
2 | 500 | 17.11.01| 3.80 |
It means that it will give me every expire date with count of product from table expire_date and match it with last buy price from table_price with product_id (always with last buy price, ordered by column buy_date)
Please guys help me, I've tried so many codes and I still can't get satysfying results
A correlated subquery using keep is possibly the most performant method:
select ed.*,
(select max(p.buy_price) keep (dense_rank first order by p.buy_date desc)
from table_price p
where p.product_id = ed.product_id
) as last_buy_price
from expire_date ed;
You could, of course, also express this in the from clause:
select ed.*, p.last_buy_price
from expire_date ed left join
(select p.product_id,
max(p.buy_price) keep (dense_rank first order by p.buy_date desc) as last_buy_price
from table_price p
) p
on p.product_id = ed.product_id;
You can use ROW_NUMBER() :
SELECT ed.*,
tp.buy_price as last_buy_price
FROM expire_date ed
JOIN(SELECT s.*,
ROW_NUMBER() OVER(PARTITION BY s.product_id ORDER BY s.buy_date DESC) as rnk
FROM table_price s) tp
ON(ed.product_id = tp.product_id and tp.rnk = 1 )
Related
I have the following data set:
| EMAIL | SIGNUP_DATE |
| A#ABC.COM | 1/1/2021 |
| B#ABC.COM | 1/2/2021 |
| C#ABC.COM | 1/3/2021 |
In order to find the running total of email signups as of a certain day, I ran the following sql query:
select
signup_date,
count(email) OVER (order by signup_date ASC) as running_total_signups
I got the following results:
| SIGNUP_DATE | RUNNING_TOTAL_SIGNUPS |
| 1/1/21 | 1 |
| 1/2/21 | 2 |
| 1/3/21 | 3 |
However for my next step, I want to be able to see not just the running total signups, but the actual signup names themselves. Therefore I want to run the same window function (count(email) OVER (order by signup_date ASC)) but instead of a count(email) just a select distinct email. This would hopefully result in the following output:
| SIGNUP_DATE | RUNNING_TOTAL_SIGNUPS |
| 1/1/21 | a#abc.com |
| 1/2/21 | a#abc.com |
| 1/2/21 | b#abc.com |
| 1/3/21 | a#abc.com |
| 1/3/21 | b#abc.com |
| 1/3/21 | c#abc.com |
How would I do this? I'm getting an error on this code:
select
signup_date,
distinct email OVER (order by signup_date ASC) as running_total_signups
One way would be to cross-join the results and filter the joined table having a total <= to the running total:
with counts as (
select *,
Count(*) over (order by SIGNUP_DATE asc) as tot
from t
)
select c1.EMAIL, c1.SIGNUP_DATE
from counts c1
cross join counts c2
where c2.tot <= c1.tot
I want to run the same window function (count(email) OVER (order by
signup_date ASC)) but instead of a count(email) just a select distinct
email
Why do you want COUNT() window function?
It has nothing to do with with your reqirement.
All you need is a simple self join:
SELECT t1.SIGNUP_DATE, t2.EMAIL
FROM tablename t1 INNER JOIN tablename t2
ON t2.SIGNUP_DATE <= t1.SIGNUP_DATE
ORDER BY t1.SIGNUP_DATE, t2.EMAIL;
which will work for your sample data, but just in case there are more than 1 rows for each day in your table you should use:
SELECT t1.SIGNUP_DATE, t2.EMAIL
FROM (SELECT DISTINCT SIGNUP_DATE FROM tablename) t1 INNER JOIN tablename t2
ON t2.SIGNUP_DATE <= t1.SIGNUP_DATE
ORDER BY t1.SIGNUP_DATE, t2.EMAIL;
See the demo.
It's actually slightly simpler than Stu proposed:
select
x2.signup_date,
x1.email
from
signups x1
INNER JOIN signups x2 ON x1.signup_date <= x2.signup_date
order by signup_date
If you join the table to itself but for any date that is less than or equal to, it causes a half cartesian explosion. The lowest dated row matches with only itself. The next one matches with itself and the earlier one, so one of the table aliases has its data repeated.. This continues adding more rows to the explosion as the dates increase:
In this resultset we can see we want the emails from x1, and the dates from x2
I have a database in SQL Server and one table which I have to use to display unique values base on column_one without using distinct so I came up with solution:
select p.id, p.one, two, w.five, p.eight
from table_one p with (nolock)
join table_two w with (nolock) on w.one = p.one
where
w.eight between convert(date, '10/05/2020', 103) and dateadd(d, 7, convert(date, '10/05/2020', 103)) and
p.twelve = 2
and p.id in (SELECT max(id) FROM table_one a with(nolock) GROUP BY two)
order by p.id desc
and I should get two rows, but I have 3, second row is duplicated? Why is that? I was trying to googling some examples and I found my solution as one of them. So what is wrong with it? Any suggestion will be helpful.
PS. I can confirm that subquery select max(id)... give me unique values.
EDITED
Sorry for missing that example earlier.
I hope is more clear now, what I want achieve.
table_one
id | one | two | eight| twelve
-------------------------------------
1 | value_1 | r1c2 | r1c8 | 2
2 | value_1 | r2c2 | r2c8 | 2
3 | value_2 | r3c2 | r3c8 | 2
4 | value_2 | r4c2 | r4c8 | 2
table_two
id | one | five | eight
---------------------------------
1 | value_1 | r1c5 | 22/03/2020
2 | value_1 | r2c5 | 24/03/2020
3 | value_2 | r3c5 | 24/03/2020
4 | value_2 | r4c5 | 25/04/2020
result expected:
id | one | two | eight
-----------------------------------
2 | value_1 | r2c2 | 24/03/2020
4 | value_2 | r4c2 | 25/04/2020
I think I figured it out, but please correct me if I am wrong, is that because I am JOINing table on column one which is not unique?
It's difficult without sample data and expected output, but I think that the following approach using ROW_NUMBER() is a possible option. You need to use the correct columns in the PARTITION BY and ORDER BY clauses:
SELECT *
FROM (
select
p.id, p.one, p.two, w.five, p.eight,
ROW_NUMBER() OVER (PARTITION BY p.two ORDER BY p.id DESC) AS rn
from table_one p with (nolock)
join table_two w with (nolock) on w.one= p.one
where
w.eight between convert(date, '10/05/2020', 103) and dateadd(d, 7, convert(date, '10/05/2020', 103)) and
p.two = 2
) t
WHERE t.rn = 1
ORDER by t.id DESC
That's true because when you join two tables on one column and it has duplicates values in that field, you get duplicate rows in your results. for your task, you can use window functions like this:
SELECT *
FROM (
select
p.*,ROW_NUMBER() OVER (PARTITION BY w.one ORDER BY w.eight DESC) AS rn
from table_one p
join table_two w on w.one= p.one
) t
WHERE t.rn = 1
ORDER by t.id asc
I have a table that stores the lines on a contract. Each contract line his it's own unique ID, it also has the ID of its parent contract. Example:
+-------------+---------+
| contract_id | line_id |
+-------------+---------+
| 1111 | 100 |
| 1111 | 101 |
| 1111 | 102 |
+-------------+---------+
I have another table that stores the historical changes to contract lines. For example, every time the number of units on a contract line is changed a new row is added to the table. Example:
+-------------+---------+--------------+-------+
| contract_id | line_id | date_changed | units |
+-------------+---------+--------------+-------+
| 1111 | 100 | 2016-01-01 | 1 |
| 1111 | 100 | 2016-02-01 | 2 |
| 1111 | 100 | 2016-03-01 | 3 |
+-------------+---------+--------------+-------+
As you can see the contract line with ID 100 belonging to the contract with ID 1111 has been edited 3 times over 3 months. The current value is 3 units.
I'm running a query against the contract lines table to select all data. I want to join to the historical data table and select the most recent row for each contract line and show the units in my results. How do I do this?
Expected results (there would single results for 101 and 102 as well):
+-------------+---------+-------+
| contract_id | line_id | units |
+-------------+---------+-------+
| 1111 | 100 | 3 |
+-------------+---------+-------+
I've tried the query below with a left join but it returns 3 rows instead of 1.
Query:
SELECT *, T1.units
FROM contract_lines
LEFT JOIN (
SELECT contract_id, line_id, units, MAX(date_changed) AS maxdate
FROM contract_history
GROUP BY contract_id, line_id, units) AS T1
ON contract_lines.contract_id = T1.contract_id
AND contract_lines.line_id = T1.line_id
Actual results:
+-------------+---------+-------+
| contract_id | line_id | units |
+-------------+---------+-------+
| 1111 | 100 | 1 |
| 1111 | 100 | 2 |
| 1111 | 100 | 3 |
+-------------+---------+-------+
An extra join to contract_history along with maxdate will work
SELECT contract_lines.*,T2.units
FROM contract_lines
LEFT JOIN (
SELECT contract_id, line_id, MAX(date_changed) AS maxdate
FROM contract_history
GROUP BY contract_id, line_id) AS T1
JOIN contract_history T2 ON
T1.contract_id=T2.contract_id and
T1.line_id= T2.line_id and
T1.maxdate=T2.date_changed
ON contract_lines.contract_id = T1.contract_id
AND contract_lines.line_id = T1.line_id
Output
This is my preferred style because it doesn't require self joining and cleanly expresses your intent. Also, it competes very well with the ROW_NUMBER() method in terms of performance.
select a.*
, b.units
from contract_lines as a
join (
select a.contract_id
, a.line_id
, a.units
, Max(a.date_changed) over(partition by a.contract_id, a.line_id) as max_date_changed
from contract_history as a
) as b
on a.contract_id = b.contract_id
and a.line_id = b.line_id
and b.date_changed = b.max_date_changed;
Another possible solution to this. This uses RANK to sort/filter this. Similar to what you did, just a different tact.
SELECT contract_lines.*, T1.units
FROM contract_lines
LEFT JOIN (
SELECT contract_id, line_id, units,
RANK() OVER (PARTITION BY contract_id, line_id ORDER BY date_changed DESC) AS [rank]
FROM contract_history) AS T1
ON contract_lines.contract_id = T1.contract_id
AND contract_lines.line_id = T1.line_id
AND T1.rank = 1
WHERE T1.units IS NOT NULL
You could change this to a INNER JOIN and remove the IS NOT NULL in the WHERE clause if you expect data to be present all the time.
Glad you figured it out!
Try this simple query:
SELECT TOP 1 T1.*
FROM contract_lines T0
INNER JOIN contract_history T1
ON T0.contract_id = T1.contract_id and
T0.line_id = T1.line_id
ORDER BY date_changed DESC
As always seems to be the way after spending an hour looking at it and shouting at StackOverflow for having a rare period of maintenance I solve my own problem not long after posting a question.
In an effort to help anyone else who's stuck I'll show what I found. It might not be an efficient way to achieve this so if someone has a better suggestion I'm all ears.
I adapted the answer from here: T-SQL Subquery Max(Date) and Joins
SELECT *,
Units = (SELECT TOP 1 units
FROM contract_history
WHERE contract_lines.contract_id = contract_history.contract_id
AND contract_lines.line_id = contract_history.line_id
ORDER BY date_changed DESC
)
FROM ....
I have the following code for example:
SELECT id, order_day, purchase_id FROM d
customer_id and purchase_id are unique. Each customer_id could have multiple purchase_id. Assume every one has made at least 5 orders.
Now, I just want to pull the first 5 purchase IDs of each customers ID (this depends on the earliest dates of purchases). I want the result to look like this:
id | purchase_id | rank
-------------------------
A | WERFEW43 | 1
A | ERTGDSFV | 3
A | FDGRT45 | 2
A | BRTE4TEW | 4
A | DFGDV | 5
B | DSFSF | 1
B | CF345 | 2
B | SDFSDFSDFS | 4
I thought of Ranking order_day, but my knowledge is not good enough to pull this off.
select id,purchase_id, rank() over (order by order_day)
from d
you also can try dense_rank() over (order by order_day) and row_number() over (order by order_day) and choose which one will be more suitable for you
select *
from
( SELECT
id
,order_day
,purchase_id
,row_number() -- ranking
over (partition by id -- each customer
order by order_day) as rn -- based on oldest dates
FROM d
) as dt
where rn <= 5
Not sure how to title or ask this really. Say I am getting a result set like this on a join of two tables, one contains the Id (C), the other contains the Rating and CreatedDate (R) with a foreign key to the first table:
-----------------------------------
| C.Id | R.Rating | R.CreatedDate |
-----------------------------------
| 2 | 5 | 12/08/1981 |
| 2 | 3 | 01/01/2001 |
| 5 | 1 | 11/11/2011 |
| 5 | 2 | 10/10/2010 |
I want this result set (the newest ones only):
-----------------------------------
| C.Id | R.Rating | R.CreatedDate |
-----------------------------------
| 2 | 3 | 01/01/2001 |
| 5 | 1 | 11/11/2011 |
This is a very large data set, and my methods (I won't mention which so there is no bias) is very slow to do this. Any ideas on how to get this set? It doesn't necessarily have to be a single query, this is in a stored procedure.
Thank you!
You need a CTE with a ROW_NUMBER():
WITH CTE AS (
SELECT ID, Rating, CreatedDate, ROW_NUMBER() OVER (PARTITION BY ID ORDER BY CreatedDate DESC) RowID
FROM [TABLESWITHJOIN]
)
SELECT *
FROM CTE
WHERE RowID = 1;
You can use row_number():
select t.*
from (select t.*,
row_number() over (partition by id order by createddate desc) as seqnum
from table t
) t
where seqnum = 1;
If you are using SQL Server 2008 or later, you should consider using windowing functions. For example:
select ID, Rating, CreatedDate from (
select ID, Rating, CreatedDate,
rowseq=ROW_NUMBER() over (partition by ID order by CreatedDate desc)
from MyTable
) x
where rowseq = 1
Also, please understand that while this is an efficient query in and of itself, your overall performance depends even more heavily on the underlying tables and, in particular, the indexes and explain plans that are used when joining the tables in the first place, etc.