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Create a new column in the R04_Table table with the following formula:

Days = COUNT([Value])

You may be surprised to see the number 1096 in this column for every row of the table. This is the count of days in all three years of the table. You may have expected to see 1 for each row in this column. This result is driven by the exception mentioned earlier when dealing with column references in row context. The aggregation function effectively switches the calculation from row context to filter context and, since there is no filter context, the final query context is all rows within the table.