OVER PARTITION BY在oracle分析数据中经常用到的函数,Min Max也会在分析中经常使用,总结一下在Linq中的用法如下
static void Main(string[] args) { var beatles = (new[] { new { id=1 , inst = "guitar" , name="john" }, new { id=2 , inst = "guitar" , name="george" }, new { id=3 , inst = "guitar" , name="paul" }, new { id=4 , inst = "drums" , name="ringo" }, new { id=5 , inst = "drums" , name="pete" } }); var rnb = beatles .OrderBy(x => x.id) // order by yyy .GroupBy(x => x.inst) // partition by xxx .Select(group => new { Group = group, Count = group.Count() }) .SelectMany(e => e.Group.Select(v => v) .Zip(Enumerable.Range(1, e.Count) /*ROW_NUMBER*/, (i, j) => new { i.inst, i.name, rn = j }) ); var min = beatles.OrderBy(x => x.id) .GroupBy(x => x.inst) .Select(group => new { Group = group, Minid = group.Min(e => e.id) }) .SelectMany(g => g.Group.Select(b => new { b.id, b.inst, b.name, minid = g.Minid })); foreach (var item in rnb) // min { Console.WriteLine("{0}|{1}|{2}", item.inst, item.name, item.rn); //Console.WriteLine("{0}|{1}|{2}", item.inst, item.name, item.minid); } Console.ReadKey(); }