Question

Greeting all.

I have a SQL Server 2008 Express database with a table called tbl_Sales, similar as following:

Merchant | Sales |  Month
Comp.1      100     201101
Comp.1      200     201102
Comp.2      130     201102
Comp.1      250     201103
Comp.2      130     201103
Comp.3      240     201103
             .
             .
             .
Comp.3      340     201111
Comp.2      240     201112
Comp.3      140     201112

I want to generate the following data in MVC3 chart.

But the chart need all merchants’ data every months else it will conflict.

So is there a way for SQL to do the result as following:

Merchant | Sales |  Month
Comp.1      100     201101
Comp.2        0     201101
Comp.3        0     201101
Comp.1      200     201102
Comp.2      130     201102
Comp.3        0     201102
Comp.1      250     201103
Comp.2      130     201103
Comp.3      240     201103
             .
             .
             .
Comp.3      340     201111
Comp.1        0     201112
Comp.2      240     201112
Comp.3      140     201112

We can have another table tbl_Merchant list out all the Merchant we need as following:

Merchant 
Comp.1
Comp.2
Comp.3
  .
  .
  .
Comp.10

Any suggestion will be welcome.

Thank you very much.

Answer 1

Yes – do a cartesian join of Merchants to Months to be reported (so that you get each month row for every merchant), then left join to your data table – like so:

select mth.[Month], mct.Merchant, coalesce(s.Sales,0) Sales
from (select distinct [Month] from tbl_Sales) mth
cross join Merchant mct
left join tbl_Sales s 
       on mth.[Month] = s.[Month] and mct.Merchant = s.Merchant

(If tbl_Sales is particularly large, it might be quicker to populate the mth inline view with the necessary range of months from a recursive CTE-generated list of months, rather than selecting the necessary set of months from the Sales data.)