|
SelectQuery qryOrder =
OQL .Select(NW.Order.OrderID, NW.Order.OrderDate, NW.Order.RequiredDate) .From(NW.Order) .Where( NW.Order.CustomerID.In(OQL .Select(NW.Customer.CustomerID) .From(NW.Customer) .Where(NW.Customer.ContactTitle == "Owner"))); |
|
The SQL statements generated as follows (taking SQL Server as an example) |
|
SELECT
[Orders].[OrderID] , [Orders].[OrderDate] , [Orders].[RequiredDate] FROM [Orders] WHERE
[Orders].[CustomerID] IN
(
SELECT [Customers].[CustomerID]
FROM [Customers]
WHERE
[Customers].[ContactTitle] = 'Owner'
) |
In order to make it easy to read and maintain, the preceding Select statements can be divided into:
|
SelectQuery qryCustomer
= OQL .Select(NW.Customer.CustomerID) .From(NW.Customer) .Where(NW.Customer.ContactTitle == "Owner"); SelectQuery qryOrder =
OQL .Select(NW.Order.OrderID, NW.Order.OrderDate, NW.Order.RequiredDate) .From(NW.Order) .Where(NW.Order.CustomerID.In(qryCustomer)); |
|
The SQL statements generated as follows (taking SQL Server as an example) |
|
SELECT
[Orders].[OrderID] , [Orders].[OrderDate] , [Orders].[RequiredDate] FROM [Orders] WHERE
[Orders].[CustomerID] IN
(
SELECT [Customers].[CustomerID]
FROM [Customers]
WHERE
[Customers].[ContactTitle] = 'Owner'
) |
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