Re: why isn't this subquery wrong?

From: jonathan vanasco <postgres(at)2xlp(dot)com>
To: pgsql-general general <pgsql-general(at)postgresql(dot)org>
Subject: Re: why isn't this subquery wrong?
Date: 2017-04-20 22:56:14
Message-ID: 0DFA6224-CC42-4A3B-B192-CE877D09960B@2xlp.com
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thanks all!

On Apr 20, 2017, at 6:42 PM, David G. Johnston wrote:

> ​Subqueries can see all columns of the parent. When the subquery actually uses one of them it is called a "correlated subquery".

i thought a correlated subquery had to note that table/alias, not a raw column. I guess i've just been adhering to good form.

On Apr 20, 2017, at 6:43 PM, Tom Lane wrote:

> Cautious SQL programmers qualify all references inside sub-selects to avoid getting caught by this accidentally.

is there a syntax to qualify a reference to lock a subquery to the current scope (disable looking at the parents)? that's how I got caught on this by accident.

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