The "Query" option, which can be found under the Census, EPA, and USGS databases, provides a way of selecting records that meet certain criteria. After a query is performed, you will be working with a subset of records rather than with the entire database.
To begin a query first click on the Query button under one of the databases. However, under the Census database or USGS database you will need to choose the geographic entity/feature type you want to query. For this example we will use Counties under the Census database. After clicking Query, a screen with blanks next to each field will appear. Click the fourth icon from the left on the bottom, the Hide-Show button , to bring up the left-hand status area.
Perhaps you would like to find out how many counties in Alabama have a "Below Poverty" rate that is less than 20%.
First be sure to put the abbreviation for Alabama (AL) in the State abbreviation field located in the center of the top line. By not filling in the appropriate state, the system will look for less than 20% Below Poverty in every county in the U.S.
Highlight the percent field box next to "Below Poverty" by clicking on it. In the left-hand status area you will see a drop box next to the word Symbols. Click here to choose an operator such as "equals", "greater than", or "less than". In this case you would choose the "less than" sign. Clicking on the sign will automatically put the operator in the field box.
When you are finished entering your operator and percent in the field box, in this case 20%, press Enter and the system will compute how many records were found with your criteria in the left-hand status area under Found. You may then look at the 37 found records in form view by using the Flipbook icon to move from one record to the next or you may use list view.
How to "AND" a Query
The query function also lets you "AND" a query. To "AND" a query choose a field and put in your operator. Then choose a second or third field and put in an operator. Hit Enter and the number of Found records that met your query will be displayed in the left-hand status bar.
How to "OR" a Query
For example, let us pretend that you wanted to do a query on the number of counties in Delaware and Maryland. After clicking the query button under Counties, you would put DE in the State abbreviation field. Next, look for the Requests menu. Under Requests, choose Add New Request. This saves your first request and allows you to enter another. You can tell how many requests have been entered/ are being worked on by looking at the number of Found records in the left-hand status bar. In the "New Request" screen put MD in the State abbreviation field and then hit Enter to see the results of your query. The number of found records for both Delaware and Maryland (27) will appear in the left-hand status area.
To see a list of records that were found as a result of your single, "and", or "or" query click Switch to List View.
To copy or export the records in the queried set to another file, go to the File menu - Export. There are a variety of file types that you can export the files in.
If you would like to view the counties that were found as a result of your query, clicking on the Show on Map button allows you to select what you would like to view on the map. Pressing the "Current" button will map the current record shown in the form. Pressing the "All" button will map all records in the set of interest and then highlight the records found from the queried set. Pressing the "Only" button will map only records found in the queried set.
When you are finished viewing the records or if you decide to perform another query on a different category, click Reset to show ALL records. All records under Counties or which ever category you are in will be restored and you can therefore begin a new search.
Source: U.S. Census Bureau
Last Revised: Thursday, 26-Jan-2012 17:47:52 EST