Re: How to parse XML in Postgres newer versions also

[Pavel Stehule <pavel.stehule@xxxxxxxxx>]

ne 17. 3. 2019 v 14:49 odesílatel Pavel Stehule <pavel.stehule@xxxxxxxxx> napsal:

Hi

ne 17. 3. 2019 v 12:11 odesílatel Andrus <kobruleht2@xxxxxx> napsal:

Hi!

In Postgres 9.1.2 script below produces proper results:

1.34
5.56

In Postgres 11 it produces wrong results:

null
null

How to make it also to work in newer versions on Postgres ?

create temp table t(x xml, nsa text[][]) on commit drop;
insert into t values(
    '<?xml version="1.0" encoding="UTF-8"?>
<Document xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns="urn:iso:std:iso:20022:tech:xsd:camt.053.001.02">
  <BkToCstmrStmt>
    <Stmt>
      <Ntry>
        <Amt Ccy="EUR">1.34</Amt>
      </Ntry>
      <Ntry>
        <Amt Ccy="EUR">5.56</Amt>
      </Ntry>
    </Stmt>
  </BkToCstmrStmt>
</Document> '::xml,
    ARRAY[ARRAY['ns','urn:iso:std:iso:20022:tech:xsd:camt.053.001.02']]);

    SELECT
    (xpath('Amt/text()', x,nsa))[1]::text::numeric AS tasusumma
    FROM (
        SELECT unnest(xpath('/ns:Document/ns:BkToCstmrStmt/ns:Stmt/ns:Ntry',
x,nsa)) as x,
        nsa
        FROM t
    ) Ntry

Andrus.

This variant is working

postgres=#  SELECT
    (xpath('/ns:Ntry/ns:Amt/text()', x,nsa))[1]::text::numeric AS tasusumma
    FROM (
        SELECT unnest(xpath('/ns:Document/ns:BkToCstmrStmt/ns:Stmt/ns:Ntry',
x,nsa)) as x,
        nsa
        FROM t
    ) Ntry
;

But I have not a idea, why old code doesn't work. It is little bit strange so it worked without namespace before Amt tag.

You can use XMLTABLE function

select xmltable.*

  from t,

          lateral xmltable(xmlnamespaces('urn:iso:std:iso:20022:tech:xsd:camt.053.001.02' as ns),

                                                         '/ns:Document/ns:BkToCstmrStmt/ns:Stmt/ns:Ntry/.' passing t.x

                                 columns tasusumma numeric path 'ns:Amt')