Use APPLY
The apply statement was created for the situation where you put multiple inline nested queries in the one statement. For example, take the following statement:
SELECT soh.SalesOrderID,
Quantity=(SELECT TOP 1 (Quantity)
FROM Sales.SalesOrderDetails
WHERE SalesOrderID = soh.SalesOrderID),
UnitPrice=(SELECT TOP 1 (UnitPrice)
FROM Sales.SalesOrderDetails
WHERE SalesOrderID = soh.SalesOrderID)
FROM Sales.SalesOrderHeader soh
This performs an extra query, retrieving data from another table using the same criterion. This can now be replaced with the following:
SELECT soh.SalesOrderID, soh.OrderDate, a.*
FROM Sales.SalesOrderHeader soh
CROSS APPLY (
SELECT TOP (1) sod.UnitPrice, sod.Quantity
FROM Sales.SalesOrderDetail sod
WHERE sod.SalesOrderId = soh.SalesOrderId
ORDER BY sod.Quantity DESC
) as a
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