I created a SQL Server database and there is a table "COST OF PRODUCTS" (> 600,000 rows). I have to make a query that shows which products have changed the price. As you can see below: 1,2,3 rows, because 1st is positive and 2nd is negative; 3rd is positive. As I understand, I must create an additional table and check using inner join or use Lag/Lead function.
Who knows what's the better way to do it?
ID | COST | CHANGE
1 | 450 | 1,4
2 | 350 | -0,8
3 | 470 | 1,2
4 | 550 | 1,3
If you just want the data listed with positive first, and then negative you can either do:
SELECT * FROM COST_OF_PRODUCTS
WHERE CHANGE>0
UNION
SELECT * FROM COST_OF_PRODUCTS
WHERE CHANGE<0
Or
SELECT * FROM COST_OF PRODUCTS
ORDER BY CHANGE
Related
I have searched google/stack to find the right answer, but what I have tried so far is not working.
Here is the problem:
I have created a table with several combinations. I am trying to find the combination that minimizes total cost.
As an example, the table looks something like this:
Combo ID | Combination | Cost
1 | 345678 | 15
2 | 345678 | 15
3 | 345678 | 18
4 | 456343 | 12
5 | 456343 | 13
So: for the combination 345678, ID #1 and #2 both minimize the cost and #4 minimizes the cost for the 456343 combination. So hopefully the query can return either the IDs 1,2,4 or it can simply return the total cost that is the minimum for that combination eg { (345678, 15), (456343, 12) }
If you want to get the IDs, you have to have a sub query that first gets the Min cost. Then you can match the combination and cost to the original Table.
SELECT Table1.ID, Table1.Combo, Table1.Cost
FROM Query1 INNER JOIN Table1 ON (Query1.MinOfCost = Table1.Cost) AND (Query1.Combo = Table1.Combo)
Query 1 :SELECT Table1.Combo, Min(Table1.Cost) AS MinOfCost FROM Table1 GROUP BY Table1.Combo
I'm really sorry as this was probably answered before, but I couldn't find something that solved the problem.
In this case, I'm trying to get the result of dividing two sums in the same column.
| Id | month | budget | sales |
| -- | ----- | ------ | ----- |
| 1 | jan | 1000 | 800 |
| 2 | jan | 1000 | 850 |
| 1 | feb | 1200 | 800 |
| 2 | feb | 1100 | 850 |
What i want is to get the % of completition for each id and month (example: get 0,8 or 80% in a fifth column for id 1 in jan)
I have something like
sel
id,
month,
sum (daily_budget) as budget,
sum (daily_sales) as sales,
budget/sales over (partition by 1,2) as efectivenes
from sales
group by 1,2
I know im doing this wrong but I'm kinda new with sql and cant find the way :|
Thanks!
This should do it
CAST(ROUND(SUM(daily_sales) * 100.00 / SUM(daily_budget), 1) AS DECIMAL(5,2)) AS Effectiveness
I'm new at SQL too but maybe I can help. Try this?
sel
id,
month,
sum (daily_budget) as budget,
sum (daily_sales) as sales,
(sum(daily_budget)/sum(daily_sales)) over (partition by id) as efectivenes
from sales
group by id
If you want to ALTER your table so that it contains a fifth column where the result of budget/sales is automatically calculated, all you need to do this add the formula to this auto-generated column. The example I am about to show is based on MySQL.
Open MySQL
Find the table you wish to modify in the Navigator Pane, right-click on it and select "Alter Table"
Add a new row to your table. Make sure you select NN (Not Null) and G (Generated Column) check boxes
In the Default/Expression column, simply enter the expression budget / sales.
Once you run your next query, you should see your column generated and populated with the calculated results. If you simply want the SQL statement to do the same from the console, it will be something like this: ALTER table YOUR_TABLE_NAME add result FLOAT as (budget / sales);
For an assignment I have to write several SQL queries for a database stored in a PostgreSQL server running PostgreSQL 9.3.0. However, I find myself blocked with last query. The database models a reservation system for an opera house. The query is about associating the a spectator the other spectators that assist to the same events every time.
The model looks like this:
Reservations table
id_res | create_date | tickets_presented | id_show | id_spectator | price | category
-------+---------------------+---------------------+---------+--------------+-------+----------
1 | 2015-08-05 17:45:03 | | 1 | 1 | 195 | 1
2 | 2014-03-15 14:51:08 | 2014-11-30 14:17:00 | 11 | 1 | 150 | 2
Spectators table
id_spectator | last_name | first_name | email | create_time | age
---------------+------------+------------+----------------------------------------+---------------------+-----
1 | gonzalez | colin | colin.gonzalez#gmail.com | 2014-03-15 14:21:30 | 22
2 | bequet | camille | bequet.camille#gmail.com | 2014-12-10 15:22:31 | 22
Shows table
id_show | name | kind | presentation_date | start_time | end_time | id_season | capacity_cat1 | capacity_cat2 | capacity_cat3 | price_cat1 | price_cat2 | price_cat3
---------+------------------------+--------+-------------------+------------+----------+-----------+---------------+---------------+---------------+------------+------------+------------
1 | madama butterfly | opera | 2015-09-05 | 19:30:00 | 21:30:00 | 2 | 315 | 630 | 945 | 195 | 150 | 100
2 | don giovanni | opera | 2015-09-12 | 19:30:00 | 21:45:00 | 2 | 315 | 630 | 945 | 195 | 150 | 100
So far I've started by writing a query to get the id of the spectator and the date of the show he's attending to, the query looks like this.
SELECT Reservations.id_spectator, Shows.presentation_date
FROM Reservations
LEFT JOIN Shows ON Reservations.id_show = Shows.id_show;
Could someone help me understand better the problem and hint me towards finding a solution. Thanks in advance.
So the result I'm expecting should be something like this
id_spectator | other_id_spectators
-------------+--------------------
1| 2,3
Meaning that every time spectator with id 1 went to a show, spectators 2 and 3 did too.
Note based on comments: Wanted to make clear that this answer may be of limited use as it was answered in the context of SQL-Server (tag was present at the time)
There is probably a better way to do it, but you could do it with the 'stuff 'function. The only drawback here is that, since your ids are ints, placing a comma between values will involve a work around (would need to be a string). Below is the method I can think of using a work around.
SELECT [id_spectator], [id_show]
, STUFF((SELECT ',' + CAST(A.[id_spectator] as NVARCHAR(10))
FROM reservations A
Where A.[id_show]=B.[id_show] AND a.[id_spectator] != b.[id_spectator] FOR XML PATH('')),1,1,'') As [other_id_spectators]
From reservations B
Group By [id_spectator], [id_show]
This will show you all other spectators that attended the same shows.
Meaning that every time spectator with id 1 went to a show, spectators 2 and 3 did too.
In other words, you want a list of ...
all spectators that have seen all the shows that a given spectator has seen (and possibly more than the given one)
This is a special case of relational division. We have assembled an arsenal of basic techniques here:
How to filter SQL results in a has-many-through relation
It is special because the list of shows each spectator has to have attended is dynamically determined by the given prime spectator.
Assuming that (d_spectator, id_show) is unique in reservations, which has not been clarified.
A UNIQUE constraint on those two columns (in that order) also provides the most important index.
For best performance in query 2 and 3 below also create an index with leading id_show.
1. Brute force
The primitive approach would be to form a sorted array of shows the given user has seen and compare the same array of others:
SELECT 1 AS id_spectator, array_agg(sub.id_spectator) AS id_other_spectators
FROM (
SELECT id_spectator
FROM reservations r
WHERE id_spectator <> 1
GROUP BY 1
HAVING array_agg(id_show ORDER BY id_show)
#> (SELECT array_agg(id_show ORDER BY id_show)
FROM reservations
WHERE id_spectator = 1)
) sub;
But this is potentially very expensive for big tables. The whole table hast to be processes, and in a rather expensive way, too.
2. Smarter
Use a CTE to determine relevant shows, then only consider those
WITH shows AS ( -- all shows of id 1; 1 row per show
SELECT id_spectator, id_show
FROM reservations
WHERE id_spectator = 1 -- your prime spectator here
)
SELECT sub.id_spectator, array_agg(sub.other) AS id_other_spectators
FROM (
SELECT s.id_spectator, r.id_spectator AS other
FROM shows s
JOIN reservations r USING (id_show)
WHERE r.id_spectator <> s.id_spectator
GROUP BY 1,2
HAVING count(*) = (SELECT count(*) FROM shows)
) sub
GROUP BY 1;
#> is the "contains2 operator for arrays - so we get all spectators that have at least seen the same shows.
Faster than 1. because only relevant shows are considered.
3. Real smart
To also exclude spectators that are not going to qualify early from the query, use a recursive CTE:
WITH RECURSIVE shows AS ( -- produces exactly 1 row
SELECT id_spectator, array_agg(id_show) AS shows, count(*) AS ct
FROM reservations
WHERE id_spectator = 1 -- your prime spectator here
GROUP BY 1
)
, cte AS (
SELECT r.id_spectator, 1 AS idx
FROM shows s
JOIN reservations r ON r.id_show = s.shows[1]
WHERE r.id_spectator <> s.id_spectator
UNION ALL
SELECT r.id_spectator, idx + 1
FROM cte c
JOIN reservations r USING (id_spectator)
JOIN shows s ON s.shows[c.idx + 1] = r.id_show
)
SELECT s.id_spectator, array_agg(c.id_spectator) AS id_other_spectators
FROM shows s
JOIN cte c ON c.idx = s.ct -- has an entry for every show
GROUP BY 1;
Note that the first CTE is non-recursive. Only the second part is recursive (iterative really).
This should be fastest for small selections from big tables. Row that don't qualify are excluded early. the two indices I mentioned are essential.
SQL Fiddle demonstrating all three.
It sounds like you have one half of the total question--determining which id_shows a particular id_spectator attended.
What you want to ask yourself is how you can determine which id_spectators attended an id_show, given an id_show. Once you have that, combine the two answers to get the full result.
So the final answer I got, looks like this :
SELECT id_spectator, id_show,(
SELECT string_agg(to_char(A.id_spectator, '999'), ',')
FROM Reservations A
WHERE A.id_show=B.id_show
) AS other_id_spectators
FROM Reservations B
GROUP By id_spectator, id_show
ORDER BY id_spectator ASC;
Which prints something like this:
id_spectator | id_show | other_id_spectators
-------------+---------+---------------------
1 | 1 | 1, 2, 9
1 | 14 | 1, 2
Which suits my needs, however if you have any improvements to offer, please share :) Thanks again everybody!
I want to combine two tables into one:
The first table: Payments
id | 2010_01 | 2010_02 | 2010_03
1 | 3.000 | 500 | 0
2 | 1.000 | 800 | 0
3 | 200 | 2.000 | 300
4 | 700 | 1.000 | 100
The second table is ID and some date (different for every ID)
id | date |
1 | 2010-02-28 |
2 | 2010-03-01 |
3 | 2010-01-31 |
4 | 2011-02-11 |
What I'm trying to achieve is to create table which contains all payments before the date in ID table to create something like this:
id | date | T_00 | T_01 | T_02
1 | 2010-02-28 | 500 | 3.000 |
2 | 2010-03-01 | 0 | 800 | 1.000
3 | 2010-01-31 | 200 | |
4 | 2010-02-11 | 1.000 | 700 |
Where T_00 means payment in the same month as 'date' value, T_01 payment in previous month and so on.
Is there a way to do this?
EDIT:
I'm trying to achieve this in MS Access.
The problem is that I cannot connect name of the first table's column with the date in the second (the easiest way would be to treat it as variable)
I added T_00 to T_24 columns in the second (ID) table and was trying to UPDATE those fields
set T_00 =
iif(year(date)&"_"&month(date)=2010_10,
but I realized that that would be to much code for access to handle if I wanted to do this for every payment period and every T_xx column.
Even if I would write the code for T_00 I would have to repeat it for next 23 periods.
Your Payments table is de-normalized. Those date columns are repeating groups, meaning you've violated First Normal Form (1NF). It's especially difficult because your field names are actually data. As you've found, repeating groups are a complete pain in the ass when you want to relate the table to something else. This is why 1NF is so important, but knowing that doesn't solve your problem.
You can normalize your data by creating a view that UNIONs your Payments table.
Like so:
CREATE VIEW NormalizedPayments (id, Year, Month, Amount) AS
SELECT id,
2010 AS Year,
1 AS Month,
2010_01 AS Amount
FROM Payments
UNION ALL
SELECT id,
2010 AS Year,
2 AS Month,
2010_02 AS Amount
FROM Payments
UNION ALL
SELECT id,
2010 AS Year,
3 AS Month,
2010_03 AS Amount
FROM Payments
And so on if you have more. This is how the Payments table should have been designed in the first place.
It may be easier to use a date field with the value '2010-01-01' instead of a Year and Month field. It depends on your data. You may also want to add WHERE Amount IS NOT NULL to each query in the UNION, or you might want to use Nz(2010_01,0.000) AS Amount. Again, it depends on your data and other queries.
It's hard for me to understand how you're joining from here, particularly how the id fields relate because I don't see how they do with the small amount of data provided, so I'll provide some general ideas for what to do next.
Next you can join your second table with this normalized Payments table using a method similar to this or a method similar to this. To actually produce the result you want, include a calculated field in this view with the difference in months. Then, create an actual Pivot Table to format your results (like this or like this) which is the proper way to display data like your tables do.
I'm trying to get a report of how many article have been sold, especially which one was sold more, both in terms of numbers and price.
I'm trying the above query, thinking that using the [PRICE]*[total] in the group by expression, it could worked. unluckily it does not. I've try also to put the alias in the group by expression, but nothing more, it only says that I need to use a grouping expression for the column: [PRICE]*[total] which is what I thought I have done.
SELECT TOP 20 ARTIC, Sum(TOTGIA) AS total, [PRICE]*[total] AS a
FROM Car
GROUP BY ARTIC, [PRICE]*[total]
ORDER BY Sum(TOTGIA) DESC;
anyone could lead me in the good direction?
the error is:
"You tried to execute a query that does not include the specified expression '[PRICE]*[total]' as part of an aggregate function."
the table is something like this:
|artic|totgia|price
+++++++++++++++++++
|aaa | 1 | 10
|aaa | 4 | 10
|bbb | 1 | 200
I would like to have:
|aaa| 5 | 50
|bbb| 1 | 200
so aaa is the first one for number of sells, but bbb is first for cash
The problem here is that you are trying to use the total alias in the select and in the group by. You do not have access to the alias at this time. Instead, you will either need to refer to the actual column values in place of total. In other cases, you can create a subselect and use the alias, but this does not apply to your query as it is written.
SELECT TOP 20 ARTIC, Sum(TOTGIA) AS total, PRICE*Sum(TOTGIA) AS a
FROM Car
GROUP BY ARTIC, PRICE
ORDER BY Sum(TOTGIA) DESC;
If you have an article listed with several different prices, this query will return several rows. So, this data:
|artic|totgia|price
+++++++++++++++++++
|aaa | 1 | 10
|aaa | 4 | 20
|bbb | 1 | 200
Would return these results:
|aaa| 1 | 10
|aaa| 4 | 80
|bbb| 1 | 200
This would happen because we have specifically told sql that we want the unique articles and prices as their own rows. However, this is probably a good thing because in the above scenario, you wouldn't want to return that aaa has a quantity of 5 with a value of 50, since the total value is 90. If this is a possible scenario for your data, you would make this query into a subselect and group all the data for the unique articles together.