Database Reference
In-Depth Information
How It Works
You specify three columns of the Address table.
select AddressID, AddressLine1, City
from Person.Address
You specify the range operator
BETWEEN
with the range of
AddressID
you want to include the records
for. Hence, it filters 200 records for the address, ranging
not
between 201 and 32521, in other words, a
total of 200 records.
where AddressID between 201 and 32521
Finding NULL Values
Null values are undefined and unknown values and represented by the
NULL
keyword. When executing
queries, it becomes important sometimes to extract
NULL
and
NOT NULL
rows separately. To support this
purpose, SQL Server provides
IS NULL
and its negation
IS NOT NULL
to be included with the
WHERE
condition clause.
Try It: Using IS NULL Operator
Open a New Query window in SQL Server Management Studio. Enter the following query, and click
Execute. You should see the results shown in Figure 5-19.
select Title, FirstName, MiddleName, LastName
from Person.Contact
where MiddleName is null
How It Works
You specify four columns of the Contact table.
select Title, FirstName, MiddleName, LastName
from Person.Contact
You specify the
WHERE
condition based on whether
MiddleName
is null. Hence, it filters 8,499 records
for the person's contact details; all the listed records have their
MiddleName
as
NULL
.
where MiddleName is null
