i need help for creating a query
Current situation:
The output table contains Ids and levels. Each Id can appear several times.
Problem:
Now I want to know if level 1 appears for an id, if so I want to mark it as number 1. If an Id has only level 2 or zero just mark it as number 0.
The output can be taken from the table below.
Use aggregation:
select id,
max(case when level = 1 then 1 else 0 end) as flag
from t
group by id;
Related
I have a table that has demographic information about a set of users which looks like this:
User_id Category IsMember
1 College 1
1 Married 0
1 Employed 1
1 Has_Kids 1
2 College 0
2 Married 1
2 Employed 1
3 College 0
3 Employed 0
The result set I want is a table that looks like this:
User_Id|College|Married|Employed|Has_Kids
1 1 0 1 1
2 0 1 1 0
3 0 0 0 0
In other words, the table indicates the presence or absence of a category for each user. Sometimes the user will have a category where the value if false, sometimes the user will have no row for a category, in which case IsMember is assumed to be false.
Also, from time to time additional categories will be added to the data set, and I'm wondering if its possible to do this query without knowing up front all the possible category names, in other words, I won't be able to specify all the column names I want to count in the result. (Note only user 1 has category "has_kids" and user 3 is missing a row for category "married"
(using Postgres)
Thanks.
You can use jsonb funcions.
with titles as (
select jsonb_object_agg(Category, Category) as titles,
jsonb_object_agg(Category, -1) as defaults
from demog
),
the_rows as (
select null::bigint as id, titles as data
from titles
union
select User_id, defaults || jsonb_object_agg(Category, IsMember)
from demog, titles
group by User_id, defaults
)
select id, string_agg(value, '|' order by key)
from (
select id, key, value
from the_rows, jsonb_each_text(data)
) x
group by id
order by id nulls first
You can see a running example in http://rextester.com/QEGT70842
You can replace -1 with 0 for the default value and '|' with ',' for the separator.
You can install tablefunc module and use the crosstab function.
https://www.postgresql.org/docs/9.1/static/tablefunc.html
I found a Postgres function script called colpivot here which does the trick. Ran the script to create the function, then created the table in one statement:
select colpivot ('_pivoted', 'select * from user_categories', array['user_id'],
array ['category'], '#.is_member', null);
I am having one view which is returning the following result:
I need to put identifier just like below image
Required output:
Explanation of Output: If you can see the image 1 and in that image release 1 has 3 dates. From that I need to get 1 as an identifier for the MAX(IMPL_DATE).In RELEASE_ID = 1, We are having 08/20/2016, 08/09/2016 and 10/31/2016. From This 10/31/2016 is the largest date. So, Need Identifier as 1 and other 2 are going to be 0. Same thing with the RELEASE_ID 2 we have 2 dates and from them 01/13/2017 is the largest date so, need 1 in that row and other's going to be 0.
Thanks In advance...
You can do this with window functions:
select t.*,
(case when rank() over (partition by portfolio_id, release_id
order by impl_date desc
) = 1
then 1 else 0
end) as indentifier
from t;
The above will assign "1" to all rows with the maximum date. If you want to ensure that only one row is assigned a value (even when there are ties), then use row_number() instead of rank().
I have some data like this as shown below:
Acc_Id || Row_No
1 1
2 1
2 2
2 3
3 1
3 2
3 3
3 4
and I need a query to get the results as shown below:
Acc_Id || Row_No
1 1
2 3
3 4
Please consider that I'm a beginner in SQL.
I assume you want the Count of the row
SELECT Acc_Id, COUNT(*)
FROM Table
GROUP BY Acc_Id
Try this:
select Acc_Id, MAX(Row_No)
from table
group by Acc_Id
As a beginner then this is your first exposure to aggregation and grouping. You may want to look at the documentation on group by now that this problem has motivated your interest in a solutions. Grouping operates by looking at rows with common column values, that you specify, and collapsing them into a single row which represents the group. In your case values in Acc_Id are the names for your groups.
The other answers are both correct in the the final two columns are going to be equivalent with your data.
select Acc_Id, count(*), max(Row_No)
from T
group by Acc_Id;
If you have gaps in the numbering then they won't be the same. You'll have to decide whether you're actually looking for a count of rows of a maximum of a value within a column. At this point you can also consider a number of other aggregate functions that will be useful to you in the future. (Note that the actual values here are pretty much meaningless in this context.)
select Acc_Id, min(Row_No), sum(Row_No), avg(Row_No)
from T
group by Acc_Id;
I have this sort of structure
ID STATUS
1 FIRSTSTAT
2 FIRSTSTAT
3 FIRSTSTAT
1 SECSTAT
3 SECSTAT
3 THIRDSTAT
3 FOURTHSTAT
3 FIFTHSTAT
I want to get the 3 back because he has all following status (FIRSTSTAT, SECSTAT, THIRDSTAT). Do you have an idea how I could make that?
It should be done by explicitely giving the statuses because other statuses exist so SELECT FROM WHERE = 'THIRDSTAT' is not ok since it should have all three statuses, not only one of them.
So I guess it should be done calculating the SUM or something like that.
I tried the following but of course, it does not work :
SELECT
FROM
WHERE
AND
AND
If the number of different status values is known to always be 3:
select id
from tablename
where status in ('FIRSTSTAT', 'SECSTAT', 'THIRDSTAT')
group by id
having count(distinct status) = 3
I have one table that contains a field "ID", "mailSent" and "serviceUsed". "mailSent" contains the time when a mail was sent and "serviceUsed" contains a counter that just says if the user has used the service for the particular mail that I have sent.
I am trying to do a report that gives me back for each ID the following two facts:
1. The last time when a user has used the service, i.e., the time when for a particular user serviceUsed != 0
2. The total number of times a user has used the service, i.e., sum(serviceUsed) for each user
I would like to display this in one view and map the result always to the particular user. I can build each of the two queries separately but do not know how to combine it into one view. The two queries look as follows:
1. Select ID, max(mailSent) from Mails where serviceUsed > 0 group by ID
2. Select ID, sum(serviceUsed) from Mails group by ID
Notice that I cannot just combine them both because I also want to show the IDs that have never used my service, i.e., where serviceUsed = 0. Hence, if I just eliminate the where clause in my first query, then I will get wrong results for max(mailSent). Any idea how I can combine both?
In other words what I want is then something like this:
ID, max(mailSent), sum(serviceUsed)
where max(mailSent) is from the first query and sum(serviceUsed) from the second query.
Regards!
Try like this
SELECT * FROM
(
Select ID, max(mailSent) from Mails where serviceUsed > 0 group by ID
UNOIN ALL
Select ID, sum(serviceUsed) from Mails group by ID
) AS T
You can write it within one Query:
SELECT ID, sum(serviceUsed), max(mailSent) from Mails group by ID;
The problem, that you don't have the serviceUsed > 0 in your second Query doesn't matter. You can sum them up too, because they have the value 0.
If you have the following input:
id serviceUsed mailSent
--------------------------
1 0 1.1.1970
1 4 3.1.1970
1 3 4.1.1970
2 0 2.1.1970
The Query should return this result:
id serviceUsed mailSent
--------------------------
1 7 4.1.1970
2 0 2.1.1970
But I wonder, where your primary key is?
You want to do this with conditional aggregation:
select ID, max(case when serviceUsed > 0 then mailSent end),
sum(serviceUsed)
from Mails
group by ID;