When running a query I need column numbers to be applied to each row so that when I use the query to create a report in SSRS I can tell the report which data to put in which column. Example:
Case 1 | Jane Doe | Col 1
Case 1 | John Doe | Col 2
Case 2 | Sally Smith | Col 1 (only name in case)
My current query uses:
DECLARE #NumOfCols int=2;
And then this to tell it how to separate the columns:
(row_number() over (partition by case_num order by child_first) + #NumOfCols - 1)% #NumOfCols + 1 as DisplayCol
The problem is, when I run the query, even if a result only has one name (so only one column is needed) my data is getting duplicated. It seems like it is making it a mandatory column 1 and column 2 even if there is no data for a second column. Like this:
Case 1 | Jane Doe | Col 1
Case 1 | John Doe | Col 2
Case 2 | Sally Smith | Col 1 (only name in case)
Case 2 | Sally Smith | Col 2 (duplicating)
I hope this makes sense. Any ideas on how to eliminate duplicating the data?
Related
SQL newbie here. I'm trying to write a query that generates a scoring table, setting null to a student's grades in a module for which they haven't yet taken their exams (on PostgreSQL).
So I start with tables that look something like this:
student_evaluation:
|student_id| module_id | course_id |grade |
|----------|-----------|-----------|-------|
| 1 | 1 | 1 |3 |
| 1 | 1 | 1 |7 |
| 1 | 2 | 1 |8 |
| 2 | 4 | 2 |9 |
course_module:
| module_id | course_id |
| ---------- | --------- |
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 2 |
In our use case, a course is made up of several modules. Each module has a single exam, but a student who failed his exam may have a couple of retries. The same module may also be present in different courses, but an exam attempt only counts for one instance of the module (ie. student A passed module 1's exam on course 1. If course 2 also has module 1, student A has to retake the same exam for course 2 if he also has access to that course).
So the output should look like this:
student_id
module_id
course_id
grade
1
1
1
3
1
1
1
7
1
2
1
8
1
3
1
null
2
4
2
9
I feel like this should have been a simple task, but I think I have a very flawed understanding of how outer and cross joins work. I have tried stuff like:
SELECT se.student_id, se.module_id, se.course_id, se.grade FROM student_evaluation se
RIGHT OUTER JOIN course_module ON course_module.course_id = se.course_id
AND course_module.module_id = se.module_id
or
SELECT se.student_id, se.module_id, se.course_id, se.grade FROM student_evaluation se
CROSS JOIN course_module WHERE course_module.course_id = se.course_id
Neither worked. These all feel wrong, but I'm lost as to what would be the proper way to go about this.
Thank you in advance.
I think you need both join types: first use a cross join to build a list of all combinations of students and courses, then use an outer join to add the grades.
SELECT sc.student_id,
sc.module_id,
sc.course_id,
se.grade
FROM student_evaluation se
RIGHT JOIN (SELECT s.student_id,
c.module_id,
c.course_id
FROM (SELECT DISTINCT student_id
FROM student_evaluation) AS s
CROSS JOIN course_module AS c) AS sc
USING (course_id));
I have a query which returns results of data, which runs on a frequent basis. The new table will contain results of the old table as well but I only want to take whatever is in new in the most recent run of the new table and send that as an email. I already have the line for the email and trade data but just need a way to be able to:
display the results of the new table to be emailed
save the complete results of the new table to be used in the next run of the query
e.g.
Old results: tbl
| idx | name | age |
| 0 | Tom | 30 |
| 1 | Jerry | 25 |
| 2 | Bob | 30 |
| 3 | Ken | 45 |
New results: tbl
| idx | name | age |
| 0 | Tom | 30 |
| 1 | Jerry | 25 |
| 2 | Bob | 30 |
| 3 | Ken | 45 |
| 4 | Sam | 40 |
output required:
| 4 | Sam | 40 |
and then save the New results to be used in the next run
Thanks! :)
If the only changes between runs is that records are being appended onto the new table, you could just keep a variable denoting the last index seen and then select only those rows where idx is larger than that.
If the indexes are always increasing, this could be achieved using a query like
lastidx:exec last idx from tbl
select from tbl where idx>lastidx
If the idx values don't always increase monotonically, you could keep a count of the number of rows instead and only
lasti:count tbl
select from tbl where i>=lasti
This doesn't require saving the whole table in memory for use in the next iteration.
E.g to start with the old table had 4 rows so lasti = 4
q)tbl
idx name age
-------------
0 Tom 30
1 Jerry 25
2 Bob 30
3 Ken 45
q)lasti
4
The new table comes in and running the command selects the new row
q)tbl
idx name age
-------------
0 Tom 30
1 Jerry 25
2 Bob 30
3 Ken 45
4 Sam 40
q)select from tbl where i>lasti
idx name age
------------
4 Sam 40
lasti can then be updated to reflect the new count
q)lasti:count tbl
q)lasti
5
One way you can get this done, assuming the idx is the unique key :
q)old:([] idx:0 1 2 3; name:`T`J`B`K; age: 30 25 30 45)
q)new:old,enlist `idx`name`age!(4; `S;40) //new output from your query
q)out:()
q)if[0<count i:new[`idx] except old[`idx] ; out:new i ; old:new]
q)out
idx name age
------------
4 S 40
Another way, if your new records are always added to the last of old records:
q)old:([] idx:0 1 2 3; name:`T`J`B`K; age: 30 25 30 45)
q)i:count old
q)new:old,enlist `idx`name`age!(4; `S;40) //new output from your query
q)out:()
q)if[i<c:count new ; out:(i-c)#new ; old:new; i:c]
q)out
idx name age
------------
4 S 40
I have a table like this
----------------------------------------------
ID Name Value |
---------------------------------------------|
1 Bob 4 |
2 Mary 3 |
3 Bob 5 |
4 Jane 3 |
5 Jane 1 |
----------------------------------------------
Is there any ways to do out a calculated field where if the name is "Bob" , it'll sum up all the values that have the name "Bob"?
Thanks in advance!
If Name = “Bob” then Value end
I've got a requirement to built a list report to show volume by 3 grouped by columns. The issue i'm having is if nothing happened on specific days for the specific grouped columns, i cant force it to show 0.
what i'm currently getting is something like:
ABC | AA | 01/11/2017 | 1
ABC | AA | 03/11/2017 | 2
ABC | AA | 05/11/2017 | 1
what i need is:
ABC | AA | 01/11/2017 | 1
ABC | AA | 02/11/2017 | 0
ABC | AA | 03/11/2017 | 2
ABC | AA | 04/11/2107 | 0
ABC | AA | 05/11/2017 | 1
ive tried going down the route of unioning a "dummy" query with no query filters, however there are days where nothing has happened, at all, for those first 2 columns so it doesn't always populate.
Hope that makes sense, any help would be greatly appreciated!
to anyone who wanted an answer i figured it out. Query 1 for just the dates, as there will always be some form of event happening daily so will always give a unique date range.
query 2 for the other 2 "grouped by" columns.
Create a data item in each with "1" as the result (but would work with anything as long as they are the same).
Query 1, left join to Query 2 on this new data item.
This then gives a full combination of all 3 columns needed. The resulting "Query 3" can then be left joined again to get the measures. Final query (depending on aggregation) may need to have the measure data item wrapped with a COALESCE/ISNULL to create a 0 on those days nothing happened.
I am trying to find for each customer the Max consecutive years he buys something. I tried to create a calculated field but to no avail.
I created two calculated fields
Consecutive: if max([Count])>0 then previous_value(0)+1+index()-index() else 0 end
max: window_max([Consecutive])
My data looks something like:
Year | Customer | Count
1996 | a | 2
1996 | b | 1
1997 | a | 1
1997 | b | 2
1998 | b | 1
So the result would be
a:2
b:3
Use nested table calcs.
The first calc, call it running_good_years, is a running count of consecutive years with sales.
If count(Sales) = 0 then 0 else previous_value(0) + 1 end
The second just returns the max
Window_max(running_good_years)
With table calcs, defining the partitioning and addressing is critical. Partition by Customer, Address by year