SharePoint search has few default columns already mapped. In case you are creating your own List and added few columns and you want SharePoint Search engine to include that column in Search result, you have to do following settings.
- Go to Central Administration.
- Under Shared Services Administration click on your SSP name.
- Go to Search -> Search Settings
- On "Configure Search Settings" page click on the "Metadata property mappings" settings.
- Click on "New managed Property"
- Choose the data type of your column in the List (Text/Integer/Decimal/Date Time/YesNo)
- Click on the Add mapping and Give few characters of your column name so that SharePoint can search that particular column.
- Now choose the column and click Ok.
- Now you can find your column in "Managed Properties View" and you can use this Mapped name in your select query.
Note: I had faced one problem while performing above steps. In step 7 while adding the column I was not able to find my column and after struggling a lot I found the solution for the same. Actually when you add any column in the List and if that column doesn't have any data In step 7 that column will not be found so to overcome this issue , before doing above steps make sure you have some data in the field you are interested in mapping in search also make sure after adding the data you have ran the "Full crawl" the site once.