How would I optimize this? I need to pull data from different tables and use results of queries in queries - sql

Question

Please propose an approach I should follow since I am obviously missing the point. I am new to SQL and still think in terms of MS Access. Here's an example of what I'm trying to do: Like I said, don't worry about the detail, I just want to know how I would do this in SQL.
I have the following tables:
Hrs_Worked (staff, date, hrs) (200 000+ records)
Units_Done (team, date, type) (few thousand records)
Rate_Per_Unit (date, team, RatePerUnit) (few thousand records)
Staff_Effort (staff, team, timestamp) (eventually 3 - 4 million records)
SO I need to do the following:
1) Calculate what each team earned by multiplying their units with RatePerUnit and Grouping on Team and Date. I create a view TeamEarnPerDay:
Create View teamEarnPerDay AS
SELECT
,Units_Done.Date,
,Units_Done.TeamID,
,Sum([Units_Done]*[Rate_Per_Unit.Rate]) AS Earn
FROM Units_Done INNER JOIN Rate_Per_Unit
ON (Units_Done.quality = Rate_Per_Unit.quality)
AND (Units_Done.type = Rate_Per_Unit.type)
AND (Units_Done.TeamID = Rate_Per_Unit.TeamID)
AND (Units_Done.Date = Rate_Per_Unit.Date)
GROUP BY
Units_Done.Date,
Units_Done.TeamID;
2) Count the TEAM's effort by Grouping Staff_Effort on Team and Date and counting records. This table has a few million records.
I have to cast the timestamp as a date....
CREATE View team_effort AS
SELECT
TeamID
,CAST([Timestamp] AS Date) as TeamDate,
,Count(Staff_EffortID) AS TeamEffort
FROM Staff_Effort
GROUP BY
TeamID
,CAST([Timestamp] AS Date);
3) Calculate the Team's Rate_of_pay: (1) Team_earnings / (2) Team_effort
I use the 2 views I created above. This view's performance drops but is still acceptable to me.
Create View team_rate_of_pay AS
SELECT
tepd.Date
,tepd.TeamID
,tepd.Earn
,tepd.TeamBags
,[Earn]/[TeamEffort] AS teamRate
FROM teamEarnPerDay
INNER JOIN team_effort
ON (teamEarnPerDay.Date = team_effort.TeamDate)
AND (teamEarnPerDay.TeamID = team_effort.TeamID);
4) Group Staff_Effort on Date and Staff and count records to get each individuals's effort. (share of the team effort)
I have to cast the Timestamp as a date....
Create View staff_effort AS
SELECT
TeamID
,StaffID
,CAST([Timestamp] AS Date) as StaffDate
,Count(Staff_EffortID) AS StaffEffort
FROM Staff_Effort
GROUP BY
,TeamID
,StaffID
,CAST([Timestamp] AS Date);
5) Calculate Staff earnings by: (4) Staff_Effort x (3) team_rate_of_pay
Multiply the individual's effort by the team rate he worked at on the day.
This one is ridiculously slow. In fact, it's useless.
CREATE View staff_earnings AS
SELECT
staff_effort.StaffDate
,staff_effort.StaffID
,sum(staff_effort.StaffEffort) AS StaffEffort
,sum([StaffEffort]*[TeamRate]) AS StaffEarn
FROM staff_effort INNER JOIN team_rate_of_pay
ON (staff_effort.TeamID = team_rate_of_pay.TeamID)
AND (staff_effort.StaffDate = team_rate_of_pay.Date)
Group By
staff_effort.StaffDate,
staff_effort.StaffID;
So you see what I mean.... I need various results and subsequent queries are dependent on those results.
What I tried to do is to write a view for each of the above steps and then just use the view in the next step and so on. They work fine but view nr 3 runs slower than the rest, even though still acceptable. View nr 5 is just ridiculously slow.
I actually have another view after nr.5 which brings hours worked into play as well but that just takes forever to produce a few rows.
I want a single line for each staff member, showing what he earned each day calculated as set out above, with his hours worked each day.
I also tried to reduce the number of views by using sub-queries instead but that took even longer.
A little guidance / direction will be much appreciated.
Thanks in advance.
--EDIT--
Taking the query posted in the comments. Did some formatting, added aliases and a little cleanup it would look like this.
SELECT epd.CompanyID
,epd.DATE
,epd.TeamID
,epd.Earn
,tb.TeamBags
,epd.Earn / tb.TeamBags AS RateperBag
FROM teamEarnPerDay epd
INNER JOIN teamBags tb ON epd.DATE = tb.TeamDate
AND epd.TeamID = tb.TeamID;

Answer 1

I eventually did 2 things:
1) Managed to reduce the nr of nested views by using sub-queries. This did not improve performance by much but it seems simpler with fewer views.
2) The actual improvement was caused by using LEFT JOIN in stead of Inner Join.
The final view ran for 50 minutes with the Inner Join without producing a single row yet.
With LEFT JOIN, it produced all the results in 20 seconds!
Hope this helps someone.