2007-10-17

.Net select column with null value from a datatable


To select a column with null value from a DataTable use the following expression:

Isnull(Col,'NULL_COLUMN') = 'NULL_COLUMN'


where Col is the name of the column, 'NULL_COLUMN' is the default return value if the column value is null.
So basically we verify if the value returned equals the anticipated null-return-value; if it does, the column value is NULL and the row containing this column will be added to the results.

string sql = "Isnull(Col,'NULL_COLUMN') = 'NULL_COLUMN'";
string sort = "Col ASC";
DataRow[] result = myTable.Select(sql, sort);


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