2011

Use Queries to Filter Database Information
A query to the database is a search criterion that you construct to return the
records you want.
Overview of Queries
Part of the fundamental power of database systems is their ability to present
a subset of records based on a search criterion or query that you specify. For
example, you might have a database table containing records of all the rooms
that exist at your company's headquarters facilities. Suppose that you want
to prepare a report that lists all conference rooms that can seat more than 20
people. Using the Query Editor, you can easily construct a query that returns
the subset of records or linked graphical objects that you want to see.
The Query Editor consists of a series of four tabs that you can use to develop
queries. The tabbed progression is designed to make working with queries
simple, even if you are not familiar with Structured Query Language (SQL). If
you are unfamiliar with queries, work with the Quick Query and Range Query
tabs initially until you become familiar with query syntax. Once you learn
the basics involved in developing meaningful queries, you can progress to the
Query Builder and SQL Query tabs.
You can begin creating a query in one tab and continue to refine it or add
additional parameters in subsequent tabs. You might, for example, begin
creating a simple query in the Quick Query tab and subsequently decide that
you would like to add an additional condition using the Query Builder tab.
When you click the Query Builder tab, it displays the values that you initially
selected using the Quick Query tab, and you can add additional conditions
to the query. However, you cannot move backwards through the tabs once
you have changed the query in one of the later tabs, because each subsequent
tab provides additional functions that are not available in the previous tabs.
If you attempt to move backwards through the query tabs after modifying a
query, you are prompted with a warning indicating that the query will be
reset with its original default values.
The tabbed progression of the Query Editor is particularly useful in becoming
familiar with SQL syntax. For example, you can create a query using the Quick
Query tab and then select the SQL Query tab to view how your query is
formatted using SQL.
The Query Editor provides the following tabs for building queries:
■ Quick Query. Provides an environment where you can develop simple
queries based on a single database field, single operator, and single value.
Use Queries to Filter Database Information | 1897