在 Oracle 中使用 XPath 和 XQuery 连接 XML 节点

Question

I have a XML data stored in CLOB column as follows:

<row id='123456' xml:space='preserve'>
<name>Martin H</name>
<phone>1111</phone>
<phone m='2'>2222</phone>
<phone m='3'></phone>
<sms m='2'>1212</sms>
<sms m='3'>2323</sms>
<email>abc@gmail.com</email>
<email m='3'>xyz@outlook.com</email></row>

How can I use Xpath and XQuery in Oracle DB to have the following expected output in only one row:

Name	Phone	Sms	Email
Martin H	1111#2222#	#1212#2323	abc@gmail.com##xyz@outlook.com

Basically, a '#' is used to separate values and any missing tag of any group from XML above is returned as a null value.

Any help will be much appreciated. Thanks!

Answer 1

Using XMLTABLE to parse your XML into columns, you can then use the string-join operator when defining the path to perform a similar functionality to LISTAGG .

WITH
    example_table (xml_clob)
    AS
        (SELECT EMPTY_CLOB () || '<row id=''123456'' xml:space=''preserve''>
    <name>Martin H</name>
    <phone>1111</phone>
    <phone m=''2''>2222</phone>
    <phone m=''3''></phone>
    <sms m=''2''>1212</sms>
    <sms m=''3''>2323</sms>
    <email>abc@gmail.com</email>
    <email m=''3''>xyz@outlook.com</email>
</row>' FROM DUAL)
SELECT xt.*
  FROM example_table  et
       CROSS JOIN
       XMLTABLE (
           'row'
           PASSING xmltype (et.xml_clob)
           COLUMNS name VARCHAR2 (100)
                       PATH 'name',
                   phone VARCHAR2 (100)
                       PATH 'string-join(phone,"#")',
                   sms VARCHAR2 (100)
                       PATH 'string-join(sms,"#")',
                   email VARCHAR2 (100)
                       PATH 'string-join(email,"#")') xt;

NAME        PHONE         SMS          EMAIL
___________ _____________ ____________ ________________________________
Martin H    1111#2222#    1212#2323    abc@gmail.com#xyz@outlook.com

Update

After reading kfinity's comment and understanding the problem a bit clearer, the problem can still be solved using XMLTABLE , then CASE statements to contatenate the values together for the desired result.

WITH
    example_table (xml_clob)
    AS
        (SELECT EMPTY_CLOB () || '<row id=''123456'' xml:space=''preserve''>
    <name>Martin H</name>
    <phone>1111</phone>
    <phone m=''2''>2222</phone>
    <phone m=''3''></phone>
    <sms m=''2''>1212</sms>
    <sms m=''3''>2323</sms>
    <email>abc@gmail.com</email>
    <email m=''3''>xyz@outlook.com</email>
</row>' FROM DUAL)
SELECT xt.name,
          CASE
              WHEN phone1_mtag IS NULL AND phone1 IS NOT NULL THEN phone1
              WHEN phone2_mtag IS NULL AND phone2 IS NOT NULL THEN phone2
              WHEN phone3_mtag IS NULL AND phone3 IS NOT NULL THEN phone3
          END
       || '#'
       || CASE
              WHEN phone1_mtag = '2' AND phone1 IS NOT NULL THEN phone1
              WHEN phone2_mtag = '2' AND phone2 IS NOT NULL THEN phone2
              WHEN phone3_mtag = '2' AND phone3 IS NOT NULL THEN phone3
          END
       || '#'
       || CASE
              WHEN phone1_mtag = '3' AND phone1 IS NOT NULL THEN phone1
              WHEN phone2_mtag = '3' AND phone2 IS NOT NULL THEN phone2
              WHEN phone3_mtag = '3' AND phone3 IS NOT NULL THEN phone3
          END    AS phone,
          CASE
              WHEN sms1_mtag IS NULL AND sms1 IS NOT NULL THEN sms1
              WHEN sms2_mtag IS NULL AND sms2 IS NOT NULL THEN sms2
              WHEN sms3_mtag IS NULL AND sms3 IS NOT NULL THEN sms3
          END
       || '#'
       || CASE
              WHEN sms1_mtag = '2' AND sms1 IS NOT NULL THEN sms1
              WHEN sms2_mtag = '2' AND sms2 IS NOT NULL THEN sms2
              WHEN sms3_mtag = '2' AND sms3 IS NOT NULL THEN sms3
          END
       || '#'
       || CASE
              WHEN sms1_mtag = '3' AND sms1 IS NOT NULL THEN sms1
              WHEN sms2_mtag = '3' AND sms2 IS NOT NULL THEN sms2
              WHEN sms3_mtag = '3' AND sms3 IS NOT NULL THEN sms3
          END    AS sms,
          CASE
              WHEN email1_mtag IS NULL AND email1 IS NOT NULL THEN email1
              WHEN email2_mtag IS NULL AND email2 IS NOT NULL THEN email2
              WHEN email3_mtag IS NULL AND email3 IS NOT NULL THEN email3
          END
       || '#'
       || CASE
              WHEN email1_mtag = '2' AND email1 IS NOT NULL THEN email1
              WHEN email2_mtag = '2' AND email2 IS NOT NULL THEN email2
              WHEN email3_mtag = '2' AND email3 IS NOT NULL THEN email3
          END
       || '#'
       || CASE
              WHEN email1_mtag = '3' AND email1 IS NOT NULL THEN email1
              WHEN email2_mtag = '3' AND email2 IS NOT NULL THEN email2
              WHEN email3_mtag = '3' AND email3 IS NOT NULL THEN email3
          END    AS email
  FROM example_table  et
       CROSS JOIN XMLTABLE ('row'
                            PASSING xmltype (et.xml_clob)
                            COLUMNS name VARCHAR2 (100) PATH 'name',
                                    phone1 VARCHAR2 (100) PATH 'phone[1]',
                                    phone1_mtag VARCHAR2 (100) PATH 'phone[1]/@m',
                                    phone2 VARCHAR2 (100) PATH 'phone[2]',
                                    phone2_mtag VARCHAR2 (100) PATH 'phone[2]/@m',
                                    phone3 VARCHAR2 (100) PATH 'phone[3]',
                                    phone3_mtag VARCHAR2 (100) PATH 'phone[3]/@m',
                                    sms1 VARCHAR2 (100) PATH 'sms[1]',
                                    sms1_mtag VARCHAR2 (100) PATH 'sms[1]/@m',
                                    sms2 VARCHAR2 (100) PATH 'sms[2]',
                                    sms2_mtag VARCHAR2 (100) PATH 'sms[2]/@m',
                                    sms3 VARCHAR2 (100) PATH 'sms[3]',
                                    sms3_mtag VARCHAR2 (100) PATH 'sms[3]/@m',
                                    email1 VARCHAR2 (100) PATH 'email[1]',
                                    email1_mtag VARCHAR2 (100) PATH 'email[1]/@m',
                                    email2 VARCHAR2 (100) PATH 'email[2]',
                                    email2_mtag VARCHAR2 (100) PATH 'email[2]/@m',
                                    email3 VARCHAR2 (100) PATH 'email[3]',
                                    email3_mtag VARCHAR2 (100) PATH 'email[3]/@m') xt;

NAME        PHONE         SMS           EMAIL
___________ _____________ _____________ _________________________________
Martin H    1111#2222#    #1212#2323    abc@gmail.com##xyz@outlook.com