Re: How do I check for NULL

From: "David G(dot) Johnston" <david(dot)g(dot)johnston(at)gmail(dot)com>
To: Thiemo Kellner <thiemo(at)gelassene-pferde(dot)biz>
Cc: pgsql-general(at)lists(dot)postgresql(dot)org
Subject: Re: How do I check for NULL
Date: 2025-12-09 17:29:17
Message-ID: CAKFQuwbnevkxuH8JUj4cRr8ABCAwhQTT7zM4kR0X_Le3tm7KMA@mail.gmail.com
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On Tue, Dec 9, 2025 at 10:14 AM Thiemo Kellner <thiemo(at)gelassene-pferde(dot)biz>
wrote:

> I feel, you meant to say, the subquery does not return any record which is
> not the same as returns NULL.
>

For a scalar subquery the final output of a zero-row query is the null
value.

David J.

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