Database Reference
In-Depth Information
If a query contains an implicit data conversion, then the normalization process adds an appropriate step to the
query tree. The process also performs some syntax-based optimization. For example, if the following query is submitted,
then the syntax-based optimization transforms the syntax of the query, as shown in the T-SQL in Figure
14-2
taken from
the
SELECT
operator properties in the execution plan, where
BETWEEN
becomes
>=
and
<=
.
SELECT soh.AccountNumber,
soh.OrderDate,
soh.PurchaseOrderNumber,
soh.SalesOrderNumber
FROM Sales.SalesOrderHeader AS soh
WHERE soh.SalesOrderID BETWEEN 62500 AND 62550;
Figure 14-2.
Syntax-based optimization
You can also see some evidence of parameterization, discussed in more detail later in this chapter. The execution
plan generated from the query looks like Figure
14-3
.
Figure 14-3.
Execution plan with a warning
