SQL から LINQ への変換、パート 7 : UNION、TOP、サブクエリ (Bill Horst)

SELECT CustomerID ID FROM CustomerTable

UNION

SELECT OrderID ID From OrderTable

(From Contact In CustomerTable _

 Select ID = Contact.CustomerID).Union(From Shipment In OrderTable _

                                       Select ID = Shipment.OrderID)

SELECT TOP 10 * FROM CustomerTable ORDER BY CustomerID

From Contact In CustomerTable Order By Contact.CustomerID Take 10

Dim digits = New Integer() {0, 1, 2, 3, 4, 5, 6, 7, 8, 9}

Dim AllDigits = From int In digits

SKIP

Dim SkipFirstTwo = From int In digits Skip 2

TAKE

Dim TakeFirstTwo = From int In digits Take 2

SKIP and TAKE together

Dim SkipTwoTakeFive = From int In digits Skip 2 Take 5

SKIP WHILE

Dim SkipUntilFour = From int In digits Skip While int Mod 5 <> 4

TAKE WHILE

Dim TakeUntilThree = From int In digits _

                     Take While int = 0 OrElse int Mod 3 <> 0

SELECT OrderID, OrderDate

FROM OrderTable

WHERE CustomerID = (SELECT CustomerID

                    FROM CustomerTable

                    WHERE City = “Seattle”)

From Shipment In OrderTable _

Where (From Contact In CustomerTable _

       Where Contact.City = “Seattle” _

       Select Contact.CustomerID).Contains(Shipment.CustomerID) _

Select Shipment.OrderID, Shipment.OrderDate

Dim SeattleOrders = From Contact In CustomerTable _

                    Join Shipment In OrderTable _

                    On Contact.CustomerID Equals Shipment.CustomerID _

                    Where Contact.City = “Seattle”

Dim FilteredOrders = From Shipment In SeattleOrders _

                     Select Shipment.OrderID, Shipment.OrderDate