Column specification (column_spec)
A column specification (
column_spec ) specifies a column in a table.Syntax
<column_spec> ::= <column_name> | <table_name>.<column_name>
| <reference_name>.<column_name> | <result_table name>.<column_name>
Explanation
For all names consisting of several
identifiers separated by a ".", any number of blanks can be specified before and after the dot.