Alias « Query Select « Oracle PL/SQL Tutorial

2.12.1.Using Column Aliases
2.12.2.Use table alias to reference column
2.12.3.Use spaces and preserve the case of your alias text
2.12.4.Use the optional AS keyword before the alias
2.12.5.An alias is required when using TO_CHAR to 'pretty up' the output
2.12.6.Column for alias
2.12.7.Sum alias
2.12.8.SUBSTR with column alias
2.12.9.Column name alias with space

2.12.10.Column name alias for count function