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From: Torsten Grust <[email protected]>
To: Rob Sargent <[email protected]>
To: pgsql-sql <[email protected]>
Subject: Re: access sub elements using any()
Date: Mon, 31 Oct 2022 23:36:56 +0100
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>
References: <[email protected]>

Hi,

On Mon, Oct 31, 2022, at 18:04, Rob Sargent wrote:
> Given an array of arrays ( e.g. v = {{1,'a'},{2,'b'},{3,'c'},{2,'d'}} ) is it possible, in plain sql, to access the first element of the listed arrays using the IN function?  Say I wanted just those with 2 as first element.  "where 2 = any(v[1])" does not work and not sure it's supported.   And I cannot craft a lhs to fussy-match each of the elements in v.  Can this be done?

if your inner arrays would be row values instead, i.e. if v would read

  v = array[(1,'a'),(2,'b'),(3,'c'),(2,'d')] :: t[]
  assuming CREATE TYPE t AS (x int, y text);

then your query could simply be

  SELECT r.*
  FROM   unnest(v) AS r
  WHERE  r.x = 2;

Cheers,
  —Torsten

--
| Torsten Grust
| [email protected]

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