Re: How to parse xml containing optional elements

Hi!

Thank you.
In "PostgreSQL 9.1.2 on x86_64-unknown-linux-gnu, compiled by gcc-4.4.real
(Debian 4.4.5-8) 4.4.5, 64-bit"

it returns two empty rows. How to make it work in this version ?

In "PostgreSQL 9.5.2, compiled by Visual C++ build 1800, 32-bit" it works.

Andrus.


-----Algsõnum-----
From: Hannes Erven
Sent: Thursday, August 11, 2016 11:51 AM
To: Andrus
Cc: pgsql-general
Subject: Re: [GENERAL] How to parse xml containing optional elements

Hi Andrus,


> SELECT
> unnest(xpath('/ns:Document/ns:BkToCstmrStmt/ns:Stmt/ns:Ntry/ns:Amt/text()',
> x,nsa))::text::numeric AS tasusumma
>     ,
> unnest(xpath('/ns:Document/ns:BkToCstmrStmt/ns:Stmt/ns:Ntry/ns:NtryDtls/ns:TxDtls/ns:Refs/ns:EndToEndId/text()',
> x,nsa))::text AS orderinr
>    FROM t;


You need to extract all ns:Ntry elements first, and then get the amount
and EndToEndId for each of them:

SELECT
(xpath('ns:Amt/text()', x,nsa))[1]::text::numeric AS tasusumma,
(xpath('ns:NtryDtls/ns:TxDtls/ns:Refs/ns:EndToEndId/text()', x,nsa))[1]
AS orderinr

FROM (
SELECT unnest(xpath('/ns:Document/ns:BkToCstmrStmt/ns:Stmt/ns:Ntry',
x,nsa)) as x, nsa
FROM t
) Ntry