doc/src/sgml/query.sgml includes a tutorial example with this definition:

CREATE TABLE weather (
...
    date            date
);

The fact that "date" is used for both the column name and the type is highlighted by two later comments:

(Yes, the column of type date is also named date. This might be convenient or confusing--you choose.)

type names are not key words in the syntax, except where required to support special cases in the SQL standard.

But as a documentation comment submitted recently points out, "date" *is* a reserved word in the SQL spec: http://www.postgresql.org/docs/current/interactive/sql-keywords-appendix.html , just not in PostgreSQL. That makes using it as a column name in an example an odd choice for a tutorial. The example is using the ambiguity to point out where the line between what is and isn't legal is at, and maybe that's a feature instead of a bug.

There are a few approaches that could improve on this:

-Keep all of that, but expand the description to link to "SQL Key Words"--right now "SQL standard" doesn't go to that section--and say this might be a reserved word in other SQL implementations. This is the smallest useful improvement.

-Change the name of the column and remove the two related descriptions. This will lose the lesson about where the parser's line is at.

-Do both: move this example of parser trivia somewhere else, but remove it from the tutorial material by using a non-reserved column name there.

--
Greg Smith   2ndQuadrant US    g...@2ndquadrant.com   Baltimore, MD
PostgreSQL Training, Services, and 24x7 Support www.2ndQuadrant.com




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