Today accidentally discovered a strange question, hope to have a great god can give me solve doubt,

The same Filter (Filter)

Use DataTable.Com pute (" SUM (column) ", the Filter) less calculation would happen (eligible records has five, but only calculated the value of four),

But using the DataView. RowFilter=Filter, and then DataView. ToTable () Compute (" SUM (column) ", null), the result is right,

What's the difference between these two kinds of writing, why sometimes less calculation above,