Okay, so we have an email database with the home address for each person in it and we need to know if we can enter a formula to search the database to find the specific cities. The column for cities is in the "G" column.
Welcome to Superuser. Knowing what version you are using helps you get a more specific answer.
The easiest solution would be to just filter your data by city. In earlier versions this is done by making a list and sorting by the column you want. In newer versions you can make a table with the data and sort it using the filter buttons in the column headings.
Here are detailed instructions how to make a list in Excel 2003.
Here are instructions how to make a table in Excel 2010.
Just highlight that column (by clicking at the top) or select the data cells you want and hit Ctrl-F. Then your search is limited to just the selected data.