I'm new to CTEs, and I am slowly starting to understand the basics.
I have a table that essentially goes in this pattern:
CUSTOMER X
CUSTOMER Y
1
1
1
2
2
3
3
4
3
5
4
5
5
6
I was wondering if a CTE would help return the numbers 1 through 6 (CUSTOMER Y) if Number 1 in CUSTOMER X had a specific column flagged for relevancy.
Customer 1 would be considered the main customer, while 2 - 6 could be stores related to said customer.
My end goal would be propogating down this relevancy flag for customers 2 - 6 if customer 1 has it and I'm currently trying to figure out how to get that full list.
I'd want the CTE to return a distinct list of customers.
CUSTOMER
1
2
3
4
5
6
Related
I would appreciate some help for below issue. I have below table
id
items
1
Product
2
Tea
3
Coffee
4
Sugar
5
Product
6
Rice
7
Wheat
8
Product
9
Beans
10
Oil
I want output like below. Basically I want to increase the rank when item is 'Product'. May I know how can I do that? For data privacy and compliance purposes I have modified the data and column names
id
items
ranks
1
Product
1
2
Tea
1
3
Coffee
1
4
Sugar
1
5
Product
2
6
Rice
2
7
Wheat
2
8
Product
3
9
Beans
3
10
Oil
3
I have tried Lag and lead functions but unable to get expected output
Here is solution using a derived value of 1 or 0 to denote data boundaries SUM'ed up with the ROWS UNBOUNDED PRECEDING option, which is key here.
SELECT
id,
items,
SUM(CASE WHEN items='Product' THEN 1 ELSE 0 END) OVER (ORDER BY id ROWS UNBOUNDED PRECEDING) as ranks
FROM
I have a requirement from client where I need to store a value against list of combination.
For example I have following LOBs and against each combination I need to store a value.
Auto
WC
Personal
I purposed multiple solutions he is not satisfied with anyone.
Solution 1: create single table, insert value against all possible combination(string) something like
LOB Value
Auto 1
WC 2
Personal 3
Auto,WC 4
Auto, personal 5
WC, Personal 6
Auto, WC, Personal 7
Solution 2: create lkp_lob, lob_group and lob_group_detail tables. Each group combination represent a group.
Lkp_lob
Lob_key Name
1 Auto
2 WC
3 Person
Lob_group (unique query constrain on lob_group_key and lob_key)
Lob_group_key Lob_key
1 1
2 2
3 3
4 1
4 2
5 1
5 3
6 2
6 3
7 1
7 2
7 3
Lob_group_detail
Lob_group_key Value
1 1
2 2
3 3
4 4
5 5
6 6
7 7
Any suggestion would be highly appreciated.
First of all I did not understood that terms you said.
But from database perspective it is always good to have multiple tables for each module. You will be facing less difficulties when doing CRUD. And will be more faster.
My company sends folks to training. Based on projected new hires/transfers, I was asked to generate a report that estimates the number of seats we need in each course broken out by quarter.
Question: My question is two-fold:
What is the best way to represent a sequence of courses (i.e. prerequisites) in a relational DB?
How do I create the query(-ies) necessary to produce the following desired output:
Desired Output:
ID PersonnelID CourseID ProjectedStartDate ProjectedEndDate
1 1 1 1/14/2017 1/14/2017
2 2 1 2/17/2017 2/17/2017
3 2 2 2/18/2017 2/19/2017
4 2 3 2/20/2017 2/20/2017
5 3 49 1/18/2017 2/03/2017
6 …
Background Info: The courses are taken in-sequence: the first few courses are orientation courses for the company, and later courses are more specific to the employee's workrole. There are over 50 different courses, 40 different workroles and we're projecting ~1k new hires/transfers. Each work role must take a sequence of courses in a prescribed order, but I'm having trouble representing this ordering and subsequently writing the necessary query.
Existing Tables:
I have several tables that I've used to store the data: Personnel, LnkPersonnelToWorkroles,Workroles, LnkWorkrolesToCourses, and Courses (there's many others as well, but I omit them for the sake of scoping this question down). Here's some notional data from these tables:
Personnel (These are the projected new hires and their estimated arrival date.)
ID DisplayName RequiredCompletionDate
1 Kristel Bump 10/1/2016
2 Shelton Franke 3/11/2017
3 Shaunda Launer 4/16/2017
4 Clarinda Kestler 3/13/2017
5 My Wimsatt 6/6/2017
6 Gillian Bramer 10/25/2016
7 ...
Workroles (These are the positions in the company)
ID Workrole
1 Manager
2 Secretary
3 Admin Asst.
4 ...
LnkPersonnelToWorkroles (Links projected new hires to their projected workrole)
ID PersonnelID WorkroleID
1 1 1
2 2 1
3 3 1
4 4 1
5 5 1
6 6 1
7 ...
Courses (All courses available)
ID CourseName LengthInDays
1 Orientation 1
2 Email Etiquette 2
3 Workplace Safety 1
4 ...
LnkWorkrolesToCourses
(Links workroles to their required courses in a Many-to-Many relationship)
ID WorkroleID CourseID
1 1 1
2 2 1
3 2 2
4 2 3
5 3 49
6 ...
Thoughts: My approach is to first develop a person-by-person schedule based upon the new hire's target completion date and workrole. Then for each class, I could sum the number of new hires starting in that quarter.
I've considered trying to represent the courses in the most general way I could think of (i.e. using a directed acyclic graph), but since most of the courses have only a single prerequisite course, I think it's much easier to represent the prerequisites using the Prerequisites table below; however, I don't know how I would use this in a query.
Prerequisites (Is this a good idea?)
ID CourseID PrereqCourseID
1 2 1
2 3 1
3 4 1
4 5 4
5 ...
Note: I am not currently concerned with whether or not the courses are actually offered on those days; we will figure out the course schedules once we know approximately how many we need each quarter. Right now, we're trying to estimate the demand for each course.
Edit 1: To clarify the Desired Output table: if the person begins course 1 on day D, then they can't start course 2 until after they finish course 1, i.e. until the next day. For courses with a length L >1 days, the start date for a subsequent courses is delayed L days. Notice this effect playing out for workrole ID 2 in the Desired Output table: He is expected to arrive on 2/17, start and complete course 1 the same day, begin course 2 the next day (on 2/18), and finish course 2 the day after that (on 2/19).
I'm posting this answer because it gives me an approximate solution; other answers are still welcome.
I avoided a prerequisite table altogether and opted for a simpler approach: a partial ordering of the courses.
First, I drew the course prerequisite tree; it looked similar to this image:
I defined a partial ordering of the courses based on their depth in the prerequisite tree. In the picture above, CHM124 and High School Chem w/ Lab are priority 1, CHM152 is priority 2, CHM 153 is priority 3, CHM260 and CHM 270 are priority 4, and so on... This partial ordering was stored in the CoursePriority table:
CoursePriority:
ID CourseID Priority
1 1 1
2 2 2
3 3 3
4 4 3
5 5 4
6 6 3
7 ...
So that no two courses would every be taken at the same time, I perturbed each course's priority by a small random number using the following Update query:
UPDATE CoursePriority SET CoursePriority.Priority = [Priority]+Rnd([ID])/1000;
(I used [ID] as input to the Rnd method to ensure each course was perturbed by a different random number.) I ended up with this:
ID CourseID Priority
1 1 1.000005623
2 2 2.000094955
3 3 3.000036401
4 4 3.000052486
5 5 4.000076711
6 6 3.00000535
7 ...
The approach above answers my first question "What is the best [sensible] way to represent a sequence of courses (i.e. prerequisites) in a relational DB?" Now as for generating the course schedule...
First, I created a query qryLnkCoursesPriorities to link Courses to the CoursePriority table:
SELECT Courses.ID AS CourseID, Courses.DurationInDays, CoursePriority.Priority
FROM Courses INNER JOIN CoursePriority ON Courses.ID = CoursePriority.CourseID;
Result:
CourseID DurationInDays Priority
1 35 1.000076177
2 21 2.000148297
3 28 3.000094352
4 14 3.000081442
5...
Second, I created the qryWorkrolePriorityDelay query:
SELECT LnkWorkrolesToCourses.WorkroleID, qryLnkCoursePriorities.CourseID AS CourseID, qryLnkCoursePriorities.Priority, qryLnkCoursePriorities.DurationInDays, ([DurationInDays]+Nz(DSum("DurationInDays","qryLnkCoursePriorities","[Priority]>" & [Priority] & ""))) AS LeadTimeInDays
FROM LnkWorkrolesToCourses INNER JOIN qryLnkCoursePriorities ON LnkWorkrolesToCourses.CourseID = qryLnkCoursePriorities.CourseID
ORDER BY LnkWorkrolesToCourses.WorkroleID, qryLnkCoursePriorities.Priority;
Simply put: The qryWorkrolePriorityDelay query tells me how many days in advance each course should be taken to ensure the new hire can complete all subsequent courses prior to their required training completion deadline. It looks like this:
WorkroleID CourseID Priority DurationInDays LeadTimeInDays
1 7 1.000060646 7 147
1 1 1.000076177 35 140
1 2 2.000148297 21 105
1 4 3.000081442 14 84
1 6 3.000082824 14 70
1 3 3.000094352 28 56
1 5 4.000106905 28 28
2...
Finally, I was able to bring this all together to create the qryCourseSchedule query:
SELECT Personnel.ID AS PersonnelID, LnkWorkrolesToCourses.CourseID, [ProjectedHireDate]-[leadTimeInDays] AS ProjectedStartDate, [ProjectedHireDate]-[leadTimeInDays]+[Courses].[DurationInDays] AS ProjectedEndDate
FROM Personnel INNER JOIN (((LnkWorkrolesToCourses INNER JOIN (Courses INNER JOIN qryWorkrolePriorityDelay ON Courses.ID = qryWorkrolePriorityDelay.CourseID) ON (Courses.ID = LnkWorkrolesToCourses.CourseID) AND (LnkWorkrolesToCourses.WorkroleID = qryWorkrolePriorityDelay.WorkroleID)) INNER JOIN LnkPersonnelToWorkroles ON LnkWorkrolesToCourses.WorkroleID = LnkPersonnelToWorkroles.WorkroleID) INNER JOIN CoursePriority ON Courses.ID = CoursePriority.CourseID) ON Personnel.ID = LnkPersonnelToWorkroles.PersonnelID
ORDER BY Personnel.ID, [ProjectedHireDate]-[leadTimeInDays]+[Courses].[DurationInDays];
This query gives me the following output:
PersonnelID CourseID ProjectedStartDate ProjectedEndDate
1 7 5/7/2016 5/14/2016
1 1 5/14/2016 6/18/2016
1 2 6/18/2016 7/9/2016
1 4 7/9/2016 7/23/2016
1 6 7/23/2016 8/6/2016
1 3 8/6/2016 9/3/2016
1 5 9/3/2016 10/1/2016
2...
With this output, I created a pivot table, where course start dates were grouped by quarter and counted. This gave me exactly what I needed.
Here is the info i have on my tables, what i need is to create a report based on certain dates and make a sum of every stock movement of the same id
Table one Table Two
Items Stocks
---------- ---------------------------
ID - NAME items_id - altas - bajas - created_at
1 White 4 5 0 8/10/2016
2 Black 2 1 5 8/10/2016
3 Red 3 3 2 8/11/2016
4 Blue 4 1 4 8/11/2016
2 10 2 8/12/2016
So based on a customer choice of dates (on this case lets say it selects all the data available on the table), i need to group them by items_id and then SUM all altas, and all bajas for that items_id, having the following at the end:
items_id altas bajas
1 0 0
2 11 7
3 3 2
4 6 4
Any help solving this?
Hope this will help:
Stock.select("sum(altas) as altas, sum(bajas) as bajas").group("item_id")
From a given table I want to be able to sum values having the same number (should be easy, right?)
Problem: A given value can be assigned from 2 to n consecutive numbers.
For some reasons this information is stored in a single row describing the value, the starting number and the ending number as below.
TABLE A
id | starting_number | ending_number | value
----+-----------------+---------------+-------
1 2 5 8
2 0 3 5
3 4 6 6
4 7 8 10
For instance the first row means:
value '8' is assigned to numbers: 2, 3 and 4 (5 is excluded)
So, I would like the following intermediairy result table
TABLE B
id | number | value
----+--------+-------
1 2 8
1 3 8
1 4 8
2 0 5
2 1 5
2 2 5
3 4 6
3 5 6
4 7 10
So I can sum 'value' for elements having identical 'number'
SELECT number, sum(value)
FROM B
GROUP BY number
TABLE C
number | sum(value)
--------+------------
2 13
3 8
4 14
0 5
1 5
5 6
7 10
I don't know how to do this and didn't find any answer on the web (maybe not looking with appropriate key words...)
Any idea?
You can do what you want with generate_series(). So, TableB is basically:
select id, generate_series(starting_number, ending_number - 1, 1) as n, value
from tableA;
Your aggregation is then:
select n, sum(value)
from (select id, generate_series(starting_number, ending_number - 1, 1) as n, value
from tableA
) a
group by n;