Index
|
Outcome
|
---|---|
There is no index defined
on any variables in the WHERE expression.
|
SAS does not continue
with the decision process. SAS must use sequential access to process
the WHERE expression.
|
There is one available
index that is defined on one or more variables in the WHERE expression.
|
SAS continues with the
decision process and determines whether using the available index
is more efficient than using sequential access.
|
There are multiple available
indexes. Each is defined on one or more of the variables in the WHERE
expression.
|
SAS continues with the
decision process. SAS must choose between the available indexes in
the next few steps. SAS tries to select the index that satisfies the
most conditions and that selects the smallest subset of observations.
|
WHERE Statement
|
Available Index
|
---|---|
where delivery_date='02jul2000'd |
simple index defined
on Delivery_Date
|
WHERE Statement
|
Available Index
|
---|---|
where order_date='01jan2000'd and delivery_date='02jul2000'd'; |
simple index defined
on Delivery_Date
|
WHERE Statement
|
Available Index
|
---|---|
where order_date='01jan2000'd and delivery_date='02jul2000'd'; |
|
WHERE Statement
|
Available Index
|
---|---|
where order_date='01jan2000'd and delivery_date='02jul2000'd'; |
composite index defined
on the following variables:
|
WHERE Statement
|
Available Index
|
---|---|
where order_date='01jan2000'd and product_id='220101400106'; |
composite index defined
on the following variables:
|
WHERE Statement
|
Available Index
|
---|---|
where delivery_date='02jul2000'd' and product_id='220101400106'; |
composite index defined
on the following variables:
|