From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
---|---|
To: | barrybrown(at)sierracollege(dot)edu |
Cc: | pgsql-bugs(at)postgresql(dot)org, pgsql-docs(at)postgresql(dot)org |
Subject: | Re: BUG #7543: Invalid table alias: DELETE FROM table * |
Date: | 2012-09-17 03:58:06 |
Message-ID: | 5536.1347854286@sss.pgh.pa.us |
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Lists: | pgsql-bugs pgsql-docs |
barrybrown(at)sierracollege(dot)edu writes:
> I sometime see my users delete all rows from a table using a command like
> this:
> DELETE FROM customer *;
> The question is: what is the star? Is it a table alias or an
> output_expression?
Neither; it specifies to search the table and its inheritance children,
ie, the opposite of ONLY. This has been the default behavior (unless
you change the setting of sql_inheritance) for many years, so "*" has
largely fallen into disuse; but it's still accepted.
However ... I went looking for documentation on this point, and I'm
darned if I can find any. There certainly used to be some, but
apparently somebody got over-eager about editing the docs to reflect
the modern default behavior. The "*" doesn't even appear in the syntax
summaries for most of the commands where it's allowed, which is flat
wrong --- anywhere you can write "ONLY tablename", it's valid to write
"tablename*" instead.
So we have some docs work to do. Thanks for pointing it out.
regards, tom lane
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