The problem is that the columns used in the ORDER BY aren’t specified in the DISTINCT. To do this, you need to use an aggregate function to sort on, and use a GROUP BY to make the DISTINCT work. Try something like this: SELECT DISTINCT Category, MAX(CreationDate) FROM MonitoringJob GROUP BY Category ORDER BY MAX(CreationDate) … Read more
Are you trying to be distinct by more than one field? If so, just use an anonymous type and the Distinct operator and it should be okay: var query = doc.Elements(“whatever”) .Select(element => new { id = (int) element.Attribute(“id”), category = (int) element.Attribute(“cat”) }) .Distinct(); If you’re trying to get a distinct set of values … Read more
Have a read through K. Scott Allen’s excellent post here: And Equality for All … Anonymous Types The short answer (and I quote): Turns out the C# compiler overrides Equals and GetHashCode for anonymous types. The implementation of the two overridden methods uses all the public properties on the type to compute an object’s hash … Read more
You can use the drop_duplicates method to get the unique rows in a DataFrame: In [29]: df = pd.DataFrame({‘a’:[1,2,1,2], ‘b’:[3,4,3,5]}) In [30]: df Out[30]: a b 0 1 3 1 2 4 2 1 3 3 2 5 In [32]: df.drop_duplicates() Out[32]: a b 0 1 3 1 2 4 3 2 5 You can … Read more
To do a distinct on only one (or n) column(s): select distinct on (name) name, col1, col2 from names This will return any of the rows containing the name. If you want to control which of the rows will be returned you need to order: select distinct on (name) name, col1, col2 from names order … Read more
You can use grouping, and get the first car from each group: List<Car> distinct = cars .GroupBy(car => car.CarCode) .Select(g => g.First()) .ToList();
DataView view = new DataView(table); DataTable distinctValues = view.ToTable(true, “Column1”, “Column2” …);
You can use this: SELECT COUNT(*) FROM (SELECT DISTINCT column_name FROM table_name) AS temp; This is much faster than: COUNT(DISTINCT column_name)
Notes.Select(x => x.Author).Distinct(); This will return a sequence (IEnumerable<string>) of Author values — one per unique value.
SELECT name,COUNT(*) as count FROM tablename GROUP BY name ORDER BY count DESC;