SQL convert from 3 to 2 columns - sql

I am trying to convert 3 columns into 2. Is there a way I can do this with the example below or a different way?
For example.
Year Temp Temp1
2015 5 6
Into:
Year Value
Base 5
2015 6

This is called unpivot, pivot is the exact opposite(make 2 columns into more) .
You can do this with a simple UNION ALL:
SELECT 'Base',s.temp FROM YourTable s
UNION ALL
SELECT t.year,t.temp1 FROM YourTable t
This relays on what you wrote on the comments, if year is constant , you can replace it with '2015'

You could use CROSS APPLY and row constructor:
SELECT s.*
FROM t
CROSS APPLY(VALUES('Base', Temp),(CAST(Year AS NVARCHAR(100)), Temp1)
) AS s(year,value);
LiveDemo

There is more than one answer to your question. Using UNION ALL seems to be the most simple solution.
I suggest reading this thread Converting Columns into rows with their respective data in sql server, as it provides a lot more details, and you can try and test how different solutions will work for you.

Related

Is there a way in Teradata convert rows into columns without changing query for new values

I am looking to convert rows to column for a requirement like sum of sales per year. A table like this can be transposed as follows:
Sales Year
100 2,005
200 2,005
300 2,006
100 2,007
200 2,006
300 2,007
'2005' '2006' '2007'
300 500 400
The query I used is
SELECT * FROM test1 PIVOT (SUM("s") FOR "y" IN ( '2005', '2006', '2007' ) ) AS Temp_pivot
However if a new year appears, say 2008 I need to modify the query.
Can I get the output for additional years without modifying the query. Can we do it without procedure or dynamic SQL?
Best Regards
Vaidy
It looks like you can use a sub-query in the IN clause, so what about something like:
SELECT *
FROM test1 PIVOT (
SUM("s") FOR "y" IN (
SELECT year_of_calendar
FROM sys_calendar.calendar
WHERE year_of_calendar >= 2005
-- '2005', '2006', '2007'
)
) AS Temp_pivot
I haven't tested it out, but give it a try and let me know.
TD Manual - Pivot
Thanks for the inputs.
Ravioli, I tried the subquery option but it says "select failed. 3669 more than one value was returned by a subquery".
Any other thoughts?
Best Regards
Vaidy

SQL Grabbing unque counts per category

I'm pretty new to SQL and Redshift, but there is a weird problem I'm getting.
So my data looks like below. Ignore id, date_time actual values... I just put random info, but its the same format
id date_time(var char 255)
1 2019-01-11T05:01:59
1 2019-01-11T05:01:59
2 2019-01-11T05:01:59
3 2019-01-11T05:01:59
1 2019-02-11T05:01:59
2 2019-02-11T05:01:59
I'm trying to get the number of counts of unique ID's per month.
I've tried the following command below. Given the amount of data, I just tried to do a demo of the first 10 rows of my table...
SELECT COUNT(DISTINCT id),
LEFT(date_time,7)
FROM ( SELECT top 10*
FROM myTable.ME )
GROUP BY LEFT(date_time, 7), id
I expect something like below.
count left
3 2019-01
2 2019-02
But I'm instead getting similar to what's below
I then tried the below command which seems correct.
SELECT COUNT(DISTINCT id),
LEFT(date_time,7)
FROM ( SELECT top 1000000*
FROM myTable.ME )
GROUP BY LEFT(date_time, 7)
However, if you remove the DISTINCT portion, you get the results below. It seems like it is only looking at a certain month (2019-01), rather than other months.
If anyone can tell me what is wrong with the commands I'm using or can give me the correct command, I'll be very grateful. Thank you.
EDIT: Could it possibly be because maybe my data isn't clean?
Why are you using a string for the date? That is simply wrong. There are built-in types. But assuming you have some reason or cannot change it, use string functions:
select left(date_time, 7) as yyyymm,
count(distinct id)
from t
group by yyyymm
order by yyyymm;
In your first query you have id in the group by which does not do what you want.

SQL find period that contain dates of specific year

I have a table (lets call it AAA) containing 3 colums ID,DateFrom,DateTo
I want to write a query to return all the records that contain (even 1 day) within the period DateFrom-DateTo of a specific year (eg 2016).
I am using SQL Server 2005
Thank you
Another way is this:
SELECT <columns list>
FROM AAA
WHERE DateFrom <= '2016-12-31' AND DateTo >= '2016-01-01'
If you have an index on DateFrom and DateTo, this query allows Sql-Server to use that index, unlike the query in Max xaM's answer.
On a small table you will probably see no difference but on a large one there can be a big performance hit using that query, since Sql-Server can't use an index if the column in the where clause is inside a function
Try this:
SELECT * FROM AAA
WHERE DATEPART(YEAR,DateFrom)=2016 OR DATEPART(YEAR,DateTo)=2016
Well you can use the following query
select * from Table1
WHERE DateDiff(day,DateFrom,DateTo)>0
AND YEAR(DateFrom) = YEAR(DateTo)
And here is the result:
Enjoy :D !

SQL of a daterange without empty spaces

I need to generate a diagram out of data from a table. This table has the following date:
Timestamp | Value
01-20-2013| 5
01-21-2013| 7
01-22-2013| 3
01-25-2013| 5
As you can see not every date has a value. If I put that into a diagram it looks weird. Dates are used for the X-axis. As 01-23-2013 and 01-24-2013 is missing this values are either not printed in the diagram (looks weird) or the are printed put the line of the diagram goes from 3 directly to 5 and not to 0 as it should.
Is there a way via SQL to select the data so that it looks like this:
Timestamp | Value
01-20-2013| 5
01-21-2013| 7
01-22-2013| 3
01-23-2013| 0
01-24-2013| 0
01-25-2013| 5
Any help is appreciated!
Regards,
Alex
Edit: I had no clue that the database engine was that important. This is running on a MySQL 5 Database (not sure about the complete version string).
There are various ways to do this, depending on the database. Date functions are notoriously database independent.
Here is an approach using a "driver" table with all dates and to use this for a left outer join:
select driver.timestamp, coalesce(t.value, 0) as value
from (select distinct timestamp + n.n as timestamp
from t cross join
(select 0 as n union all select 1 union all select 2 union all select 3
)
) driver left outer join
t;
This version assumes that there are gaps of no more than three days.
In some databases, you can construct the list of dates using a recursive CTE. Such an approach would handle gaps of any size.

Obtain maximum row_number inside a cross apply

I am having trouble in calculating the maximum of a row_number in my sql case.
I will explain it directly on the SQL Fiddle example, as I think it will be faster to understand: SQL Fiddle
Columns 'OrderNumber', 'HourMinute' and 'Code' are just to represent my table and hence, should not be relevant for coding purposes
Column 'DateOnly' contains the dates
Column 'Phone' contains the phones of my customers
Column 'Purchases' contains the number of times customers have bought in the last 12 months. Note that this value is provided for each date, so the 12 months time period is relative to the date we're evaluating.
Finally, the column I am trying to produce is the 'PREVIOUSPURCHASES' which counts the number of times the figure provided in the column 'Purchases' has appeared in the previous 12 months (for each phone).
You can see on the SQL Fiddle example what I have achieved so far. The column 'PREVIOUSPURCHASES' is producing what I want, however, it is also producing lower values (e.g. only the maximum one is the one I need).
For instance, you can see that rows 4 and 5 are duplicated, one with a 'PREVIOUSPURCHASES' of 1 and the other with 2. I don't want to have the 4th row, in this case.
I have though about replacing the row_number by something like max(row_number) but I haven't been able to produce it (already looked at similar posts at stackoverflow...).
This should be implemented in SQL Server 2012.
Thanks in advance.
I'm not sure what kind of result set you want to see but is there anything wrong with what's returned with this?
SELECT c.OrderNumber, c.DateOnly, c.HourMinute, c.Code, c.Phone, c.Purchases, MAX(o.PreviousPurchases)
FROM cte c CROSS APPLY (
SELECT t2.DateOnly, t2.Phone,t2.ordernumber, t2.Purchases, ROW_NUMBER() OVER(PARTITION BY c.DateOnly ORDER BY t2.DateOnly) AS PreviousPurchases
FROM CurrentCustomers_v2 t2
WHERE c.Phone = t2.Phone AND t2.purchases<=c.purchases AND DATEDIFF(DAY, t2.DateOnly, c.DateOnly) BETWEEN 0 AND 365
) o
WHERE c.OrderNumber = o.OrderNumber
GROUP BY c.OrderNumber, c.DateOnly, c.HourMinute, c.Code, c.Phone, c.Purchases
ORDER BY c.DateOnly