When qualifying a column name and table name in the same statement, be sure to use the same qualifying expressions for each; they are evaluated as strings and must match; otherwise, an error is returned. Example 2 is incorrect because the syntax style for the column name does not match the syntax style used for the table name.
select demo.mary.publishers.city
from demo.mary.publishers
city
-----------------------
Boston
Washington
Berkeley
select demo.mary.publishers.city
from demo..publishers
The column prefix "demo.mary.publishers"
does not match a table name or alias name used in the query.
