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POSQL Reporting - Is it better to copy data first into a temporary table
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  1. POSQL Reporting - Is it better to copy data first into a temporary table
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    copied!<p>We have tables in the following format:</p> <pre><code>Order(OrderID,CustomerID,OrderDate,CreatedByUserID,LastModifiedByUserID) OrderItem(OrderID,ProductID,ProviderID,ItemStatus,CompletedByUserID) Companies(CompanyID, CompanyName, CompanyParentID, CompanyRegionID) </code></pre> <p>The full data table required for generating reports for Orders requires almost 12 joins and about 250 fields. Below is a short example</p> <pre><code>SELECT o.OrderID, o.CustomerID ... FROM Orders AS o INNER JOIN OrderItems AS items ON o.OrderID = items.OrderID INNER JOIN Products AS p ON items.ProductID = p.ProductID INNER JOIN Companies AS cust ON o.CustomerID = cust.ComapnyID LEFT OUTER JOIN Companies AS prov ON items.ProviderID = prov.ComapnyID INNER JOIN Users AS u1 ON items.CreatedByUserID = u1.UserID INNER JOIN Users AS u2 ON items.LastModifiedByUserID = u2.UserID LEFT OUTER JOIN Users AS ui1 ON items.CompletedByUserID = ui1.UserID LEFT OUTER JOIN Users AS ui2 ON items.VerifiedByUserID = ui2.UserID LEFT OUTER JOIN Companies AS parent ON cust.CompanyParentID = parent.ComapnyID LEFT OUTER JOIN Companies AS region ON cust.CompanyRegionID = region.ComapnyID </code></pre> <p><strong>My question is:</strong> SInce this is a reporting application, should we run this SQL once (e.g. every hour) and copy the data to a temp table from which the reports are run, or should we always run all these joins whenever a user requests to see the report?</p> <p><strong>Note:</strong></p> <ol> <li>The reports can be up to an hour out of date. Since they are typically run on a weekly/monthly basis.</li> <li>The data is multi-tenant. i.e. it is filtered depending on who is running reports (customers, parent companies, regional offices, product providers etc.)</li> </ol>
 

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