CREATE TABLE test_xml_read_table(xml text);

INSERT INTO test_xml_read_table (xml)
VALUES (
'<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<maininfo count="3">
    <info price="1472.0">
    </info>
    <info price="861.0">
    </info>
    <info price="933.0">
    </info>
</maininfo>'
);

1472.0
861.0
933.0

{1472.0,861.0,933.0}

SELECT 
xpath('//maininfo/info/@price', xml::xml) price
FROM test_xml_read_table

SELECT
unnest(xpath('//maininfo/info/@price', xml::xml)) price
FROM test_xml_read_table;