Use the AS clause to rename a field to a label of your choice. The label is also referred to as an alias.
field_expression AS alias
Returns the field with the specified alias. The alias may be any valid identifier (a letter followed by any number of letter or digit characters) or a value in quotes. If the value of the alias contains spaces or special characters, it must be in quotes. For a list of special characters, see ADQL Expressions.
SELECT eventTimestamp AS 'Time Stamp' FROM transactions WHERE application='yourAppName'