... statements gives you the possi-
bility of much greater flexibility.
The term parameter in SQL statements is similar to the term variable, as it is used
in other computer languages. A parameter ... ure is executed, the calling program passes a value for the
parameter, and the SQL statement is executed as if that value were part of the
statement.
It should also be noted that...
... that time.
Generally speaking, there are three major components of the SQL language. The
first is called DML, or Data Manipulation Language. This module of the language
allows you to retrieve, ... been The Logic of SQL. This is because, like all computer languages, the
language of SQL has much more to do with cold, hard logic than with English
vocabulary.
Nevertheless,...
... statement.
The
FROM keyword is used to designate the table from which data is to be
retrieved. The name of the table follows the
FROM. In this case, the table name is
Customers.
As is the custom, ... such, the principles of
database design will be much more meaningful after you’re more aware of the
details and nuances of retrieving some data. So we’re going to tempor...
... define the logic of the
CASE expression. The WHEN and THEN keywords
define a condition that is evaluated. If the value after the
WHEN is true, then the
result after
THEN is utilized. The WHEN and THEN ... value2 THEN result2
(repeat WHEN-THEN any number of times)
[ELSE DefaultResult]
END
As can be seen, the CASE expression utilizes a number of keywords other than
CASE: W...
... rows
where the Quan tityPurchased column has a value of 5.
In the real world, the selection of data is often far from straightforward.
Accordingly, let’s now turn our attention to ways of specifying ... in the row
for William Smith. Therefore, it determines that both the William Smith and the
Natalie Lopez rows meet the condition.
Obviously, this isn’t what was meant. This...
... Customers.CustomerID
Two blank lines were inserted to clearly separate the subquery from the rest of
the statement. The subquery is the middle section of the statement.
Using a Subquery as a Data Source 143
chapter ... or
view. Notice that the subquery is given a table alias of CashOrders, which allows
the columns in the subquery to be referenced in the main
SELECT....
... OS
is a registered trademark of Apple Inc. PostgreSQL is a trademark of
PostgreSQL Inc and the Regents of the University of California.
Allothertrademarksarethepropertyoftheirrespectiveowners.
Allimages†CengageLearningunlessotherwisenoted.
LibraryofCongressControlNumber:2010925128
ISBN-13:978-1-4354-5751-5
ISBN-10:1-4354-5751-X
Course ... Lisa
The
Language of SQL
Larry Rocko...
... The AND Operator 72
The OR Operator 73
Using Parentheses 73
Multiple Sets of Parentheses 75
The NOT Operator 76
The BETWEEN Operator 79
The IN Operator 80
Boolean Logic ... area of expertise is with data warehouse
systems and reporting tools. He recently developed a suite of BI tools for ASA P
Software, a subsidiary of Dell Inc. He holds an MBA from the University of
Chi...
... the
introduction of any book they happen to read and then proceed immediately to
the first real chapter.
With that fact firmly in mind, we will only cover relatively unimportant material
in the ... Appendix D, for a description of the files available on the companion
Web site. These files list all SQL statements and provide all data shown in
the book.
You may download the co...
... stored in any number of
tables. The term relational is used to indicate that the tables are related to each
other. For example, let’s take the simple case of a database consisting of only two
tables: ... and the data they contain. The
common custom is to display a table as a grid of rows and columns. Each row
represents a record in the table. Each column represents a field...