I am trying to CROSS JOIN two tables, customers and items, so I can then create a sales by customer by item report. I have 2000 customer and 2000 items.
SELECT customer_name FROM customers; --Takes 100ms
SELECT item_number FROM items; --Takes 50ms
SELECT customer_name, item_number FROM customers CROSS JOIN items; Takes 200000ms
I know this is 4 million rows, but is it possible to get this to run any faster? I want to eventually join this with a sales table like this:
SELECT customer_name, item_number, sales_total FROM customers CROSS JOIN items LEFT JOIN sales ON (customer.customer_name = sales.customer_name, item.item_number=sales.item_number);
The sales table will obviously not have all customers or all items, so the goal here is to have a report that shows all customers and all items along with what was sold and not sold.
I'm using PostgreSQL 8.4
To answer your question: No, you can't do a cross join faster than that - if you could then that would be how CROSS JOIN would be implemented.
But really you don't want a cross join. You probably want two separate queries, one which lists all customers, and another which lists all items and whether or not they were sold.
This really needs to be multiple reports. I can think of several off the top of my head that will yield more efficient packaging of information:
Report: count of all purchases by customer/item (obvious).
Report: list of all items not purchased, by customer.
Report: Summary of Report #2 (count of items) in order to prioritize which customers to focus on.
Report: list of all customer that have not bought an item by item.
Report: Summary of Report #3 (count of customers) in order to identify both the most popular and unpopular items for further action.
Report: List of all customers who purchased an item in the past, but did not purchase it his reporting period. This report is only relevant when the sales table has a date and the customers are expected to be regular buyers (i.e. disposable widgets). Won't work as well for things like service contracts.
The point here is that one should not insist that the tool process every possible outcome at once and generate more data and anyone could possibly digest manually. One should engage the end-users and consumers of the data as to what their needs are and tailor the output to meet those needs. It will make both sides' lives much easier in the long run.
If you wish to see all items for a given client (even if the cient has no items), i would rather try
SELECT c.customer_name, i.item_number, s.sales_total
FROM customers c LEFT JOIN
sales s ON c.customer_name = s.customer_name LEFT OIN
items i on i.item_number=s.item_number
This should give you a list of all clients, and all items joined by sales.
Perhaps you want something like this?
select c.customer_name, i.item_number, count( s.customer_name ) as total_sales
from customers c full join sales s on s.customer_name = c.customer_name
full join items i on i.item_number = s.item_number
group by c.customer_name, i.item_number
Related
hope you all are good .I new to tally and I have a new situation ,I have provided the details below
1.we Own a supermarket and which contains some other departments as well
2.only one counter is available for this supermarket section
3.so the sales of other departments also get mixed with the total sale
Task :- when I enter this data into tally I have to show the other departments sales seperatly on balance sheet, how to achieve this
The Profit & Loss statement in Tally shows you the sales data of every Sales ledger separately. So, to have data on separate sales for separate departments, you will have to make different sales ledgers for different departments and make the entries accordingly.
If you are using combined single ledger for all sales, then you should make three ledgers now for sales of each of the three departments. If you are using sales ledger item wise or tax slab wise, then you need to create similar ledgers for every department and take care of choosing the right ledger when creating the voucher.
Currently I have a crystal report that only shows orders which included a "Storm Door" OR a "Sunroom Component". However I would like it to only show orders that include BOTH "Storm Door" AND "Sunroom Component" within a order. Any suggestions on how the code for this might look?
I think you have answered your own question - If you want the report to retrieve records where BOTH products were ordered, you would use an AND statement - {Categories.Description} = "Storm Doors" and {Categories.Description} = BetterView Sunroom Compnents". However, the issue with duplicate records sounds like a problem with the design of the report. You could try a few things
Look at the table joins and verify they are setup correctly; if you have a 'one to many' join setup, you may be retrieving multiple rows for each record. If you joined Customer to Orders on the Customer_ID, you would get every single order for each customer, etc.
Click Database > Select Distinct Records - Depending on how your report is configured and which fields you are displaying, this may remove the undesired duplicates.
Change your grouping order - Instead of grouping by Category (Storm door, Subroom), group by Customer and then count the number of orders or use an aggregate function to give you the information you need.
Working with vehicle asset management and I am selecting data based on two statements:
({EQ_MAIN.PROCST_PROC_STATUS} in ["A", "AS", "AT"] and
{EQ_MAIN.DEPT_DEPT_CODE} like "P*" and
{EQ_MAIN.ASSET_TYPE} <> "COMPONENT")
or
({EQ_MAIN.PROCST_PROC_STATUS} in ["TA"] and
{EQ_MAIN.DEPT_TEMP_LOANED_TO} like "P*" and
{EQ_MAIN.ASSET_TYPE} <> "COMPONENT")
Basically, if the Equipment is in status A, AS, or AT and belongs to the departments that start with P, I want it to show on the report. However, the second part of the selection statement accounts for equipment that is temporarily loaned to another department (status TA). The selection statements seem to be working fine.
I have this data grouped by {EQ_MAIN.DEPT_DEPT_CODE}. But I want it to to include any temporarily loaned out equipment under the department group, if the equipment is on temp loan to said department. For example, Car A belongs to department K1234, but is on loan to department P5678. I want Car A to show up under the group for P5678 along with all the other vehicles that belong to P5678. Essentially, whether a piece of eq belongs to a specific department or is simply on loan to said specific department, I want to see them under the same group in Crystal. Thoughts?
I do not believe that a grouping formula is the solution for this scenario. The challenge is based in the recordset. Since there is only one LOANED_TO record per DEPT_CODE, you can go about this a couple of ways.
If this is an option, modify your query or view so that you generate all LOANED_TO records for each DEPT_CODE. This could be achieved by placing a subquery in your FROM clause if using SQL. Then, join your parent table EQ_MAIN to the subquery on a non-unique, general key. Since there is no one-to-one relationship in this scenario, you should get all LOANED_TO records for each DEPT_CODE. This will, however, bloat your recordset and mar performance.
Then, group the report first on {DEPT_CODE} and second on {LOANED_TO}. Use a suppression formula on the second group to hide any {LOANED_TO} Departments that do not match the parent group {DEPT_CODE}.
The more "traditional" Crystal approach is to group on {DEPT_CODE}. Then, add a sub report to a group section. Using the same datasource, move the second chunk of selection criteria (following the OR clause) to the sub report record selection. This will return all {LOANED_TO} records. Add a sub report link between the group {DEPT_CODE} and the sub report {LOANED_TO} dept. This will filter results to just those {LOANED_TO} records related to the main group.
I have a question here. we have a customer list and product list and sale table. We want to show each customer to buy each product's total sale.
so I use the query like following:
select ...
from ...
where customer="" and product="".
the query is standard simple one. but the table/dashboard is 20*10. It means for each customer and product pair i have to run a query. i have to run query 200 times. which is super slow.
how to improve this? thanks
right now the dashboard give me 20 customer and 10 product and then i go to database for 200 times. it is from a customer list to pick first 20 and another 20 like this way. the product is the same way to choose.
You can use group by ... Something like
Select customer, product, sum(sales) -- or whatever you need
From ...
Group by customer, product
The server would do the aggregation, and the query is much faster than doing 200 queries
I'm trying to show employees at a company grouped by worked and still working (in vs2005 crystal reports).
The user can pass by parameter a list of companies they want to show.
Tables: VRP-COMPANY, VRP-COMPANY-OPPORTUNITY, VRP-OPPORTUNITY-PRODUCT
The record selection formula: {VRP-COMPANY.COMPANY company} in {?companies}
Grouping is done on: VRP-COMPANY.COMPANY company, then formula to decide its working or worked and then on productname.
Now when I run the report I only get to see the companies who have got entries in the VRP-COMPANY-OPPORTUNITY. I want to see the company name (group) even if there are no entries in the opportunity table. How to do this in Crystal Reports? I tried Left join between company and company-opportunity tabel but no effect.
I found the problem. Left join was correct but I had an additional select formula (on opportunity status to be closed-won. Therefore it let out the record. The record can also be null when there are no opportunities.
Should the question be deleted?