On 2015-07-08 11:29:55 +0000, atulcs178@gmail.com wrote:
> PostgreSQL database displays data of the first column,under second column
> name, When we merge two columns in the Select statement. However it should
> throw error if we don't put any comma (,) in between both columns.
You mean like "SELECT column_a column_b", right? In that case column_b
is the alias for column_a. The SQL standard has made the AS for column
aliases optional.
Regards,
Andres