Implement Type 2 table - merge query - sql

I have a current table:
ID
Name
Salary
Status
1
John
50,000
Active
2
Joe
55,000
Active
3
Jake
40,000
Inactive
4
James
80,000
Active
This table is created using a truncate reload query. However I want to now record historical data using a type 2 table. I know I need to add a start and end date field to indicate whether a row is the current or historical data for an employee.
Lets say the next day the source table looks like such:
ID
Name
Salary
Status
1
John
55,000
Active
2
Joe
55,000
Inactive
3
Jake
40,000
Inactive
4
James
80,000
Active
Where John got a increase Salary, and Joe is now inactive.
I want my Type 2 table to now look like:
ID
Name
Salary
Status
start date
end date
active flag
1
John
55,000
Active
10-26-2022
null
Y
1
John
50,000
Active
10-25-2022
10-26-2022
N
2
Joe
55,000
Active
10-26-2022
null
Y
2
Joe
55,000
Inactive
10-25-2022
10-26-2022
N
3
Jake
40,000
Inactive
10-26-2022
null
Y
4
James
80,000
Active
10-26-2022
null
Y
I am not familiar with creating a merge query to create this sort of performance, how can I go about doing so?

Related

SQL Db2 - How to unify two rows in one using datetime

I've got a table where we have registries of employees and where they have worked. In each row, we have the employee's starting date on that place. It's something like this:
Employee ID
Name
Branch
Start Date
1
John Doe
234
2018-01-20
1
John Doe
300
2019-03-20
1
John Doe
250
2022-01-19
2
Jane Doe
200
2019-02-15
2
Jane Doe
234
2020-05-20
I need a query where the data returned looks for the next value, making the starting date on the next branch as the end of the current. Eg:
Employee ID
Name
Branch
Start Date
End Date
1
John Doe
234
2018-01-20
2019-03-20
1
John Doe
300
2019-03-20
2022-01-19
1
John Doe
250
2022-01-19
---
2
Jane Doe
200
2019-02-15
2020-05-20
2
Jane Doe
234
2020-05-20
---
When there is not another register, we assume that the employee is still working on that branch, so we can leave it blank or put a default "9999-01-01" value.
Is there any way we can achieve a result like this using only SQL?
Another approach to my problem would be a query that returns only the row that is in a range. For example, if I look for what branch John Doe worked in 2020-12-01, the query should return the row that shows the branch 300.
You can use LEAD() to peek at the next row, according to a subgroup and ordering within it.
For example:
select
t.*,
lead(start_date) over(partition by employee_id order by start_date) as end_date
from t

Crosstab query to get results of three tables based on results table

This request might be asked many times but I have done a search last night to figure out but I came up with nothing.
I have three tables
Table A
ID
City
1
LA
2
NY
3
LV
Table B
ID
Job
11
Programmer
22
Engineer
33
Database Administrator
44
Cyber Security Analyst
Table C
ID
Job level
111
Junior
222
Associate
333
Senior
444
Director
Final table
ID
EmployeeName
City_ID
Job_ID
Level_ID
1000
Susie
1
11
333
1001
Nora
2
11
222
1002
Jackie
2
22
111
1003
Mackey
1
11
444
1004
Noah
1
11
111
I’d like to have a crosstab query using Microsoft Access that returns the following result ( based on city )
LA Table
Jobs
Junior
Associate
Senior
Director
Programmer
1
-
1
1
Engineer
-
-
-
-
Database Administrator
-
-
-
-
Cyber Security Analyst
-
-
-
-
How can I do it?
The best approach for this is always:
Create a "base" query that joins the base tables and returns all data columns that you will need for the crosstab query.
Run the crosstab query wizard using the "base" query as input.

Sum of field in a consecutive period based on a condition

I did this without complicated query and with Python. But I'm looking for a way to do this with Django ORM.
I have a table as follows:
user
date
point
Mary
2022/01/04
13
John
2022/01/04
10
Mary
2022/01/03
0
John
2022/01/03
5
Mary
2022/01/01
1
John
2022/01/01
1
Mary
2021/12/31
5
I want to calculate the Sum of points from now() to the date when the point value is greater than one.
Desired Output:
user
sum
Mary
14
13+1
John
10
10

Function to get rolling average with lowest 2 values eliminated?

This is my sample data with the current_Rating column my desired output.
Date Name Subject Importance Location Time Rating Current_rating
12/08/2020 David Work 1 London - - 4
1/08/2020 David Work 3 London 23.50 4 3.66
2/10/2019 David Emails 3 New York 18.20 3 4.33
2/08/2019 David Emails 3 Paris 18.58 4 4
11/07/2019 David Work 1 London - 3 4
1/06/2019 David Work 3 London 23.50 4 4
2/04/2019 David Emails 3 New York 18.20 3 5
2/03/2019 David Emails 3 Paris 18.58 5 -
12/08/2020 George Updates 2 New York - - 2
1/08/2019 George New Appointments5 London 55.10 2 -
I need to use a function to get values in the current_Rating column.The current_Rating gets the previous 5 results from the rating column for each name, then eliminates the lowest 2 results, then gets the average for the remaining 3. Also some names may not have 5 results, so I will just need to get the average of the results if 3 or below, if 4 results I will need to eliminate the lowest value and average the remaining 3. Also to get the right 5 previous results it will need to be sorted by date. Is this possible? Thanks for your time in advance.
What a pain! I think the simplest method might be to use arrays and then unnest() and aggregate:
select t.*, r.current_rating
from (select t.*,
array_agg(rating) over (partition by name order by date rows between 4 preceding and current row) as rating_5
from t
) t cross join lateral
(select avg(r) as current_rating
from (select u.*
from unnest(t.rating_5) with ordinality u(r, n)
where r is not null
order by r desc desc
limit 3
) r
) r

Combine 2 queries into 1 table with user entering the parameters twice for both queries

My project needs me to come up with a query which can compare any 2 months data side by side, by just keying in the dates of the 2 months.
I have done 2 separate queries that can only do single month data because I can only enter 1 date per query. I tried to combine this 2 separate query into 1 single query by selecting the columns from each table but it gives me blank data.
I will need some help in combining the 2 queries together, into 1 table as a view form and allowing the user to key in the 2 dates they want to get their data from. Below will be the 2 queries result I can achieve and also the end result I want to achieve from combining this 2 queries.
Conditions to merge the two table is that the company will be the same for both dates, and the item the company bought (if any). If the company did not buy the item on the month , data should be blank.
Query 1 : User will enter "First month" they want the data from
Inv Number Company Date Item Price Quantity Total
123 ABC 1/1/2018 Table 5 3 15
123 ABC 1/1/2018 Chair 2 4 8
345 XYZ 1/1/2018 Table 5 5 25
345 XYZ 1/1/2018 Chair 2 6 12
Query 2: User will enter "Second Month" they want the data from
Inv Number Company Date Item Price Quantity Total
999 ABC 1/2/2018 Table 4 3 12
999 ABC 1/2/2018 Chair 2 5 10
899 XYZ 1/2/2018 Table 4 3 12
End result : User will be allowed to key in both dates they want the data from
Inv Number Company Date Item Price Quantity Total Date Item Price Quantity Total Inv Number
123 ABC 1/1/2018 Table 5 3 15 1/2/2018 Table 4 3 12 999
123 ABC 1/1/2018 Chair 2 4 8 1/2/2018 Chair 2 5 10 999
345 XYZ 1/1/2018 Table 5 5 25 1/2/2018 Table 4 3 12 899
345 XYZ 1/1/2018 Chair 2 6 12