Column Name

A long identifier that designates a table, view or result column. A column-name may be qualified or unqualified. A qualified column-name is prefixed with a qualifier followed by a period. A qualifier may be a table-name, view-name, correlation-name, or query-name.

The column name can be used to:

• Define the name of the column in a table or view, as in a CREATE TABLE command.
• Identify a column in a table or view, as in a CREATE INDEX or a COMMENT ON command.
• Specify values of a column or intermediate result, as in a function, expression, GROUP BY clause, ORDER BY clause, or search condition.

In the above contexts only, column names may be qualified by prefixing them with a table name, view name or correlation name, followed by a period. Qualification is used to express correlated references, or to resolve ambiguous references. It can also be used simply as a matter of convenience.

Note that column names must be qualified when appearing in COMMENT ON commands.