Question

当我遇到以下问题时，我正在学习XMLType应用程序。它正在返回CD标题的NULL内容。我不确定为什么它会以这种方式表现。

DROP TABLE  Xml_tab;
 /
 CREATE TABLE Xml_tab ( xmlval xmltype);
 /
INSERT INTO Xml_tab
VALUES(XMLTYPE.CREATEXML(
  '<CATALOG><CD><TITLE>Empire Burlesque</TITLE><ARTIST>Bob Dylan</ARTIST><COUNTRY>USA</COUNTRY><COMPANY>Columbia</COMPANY><PRICE>10.90</PRICE><YEAR>1985</YEAR></CD><CD><TITLE>Hide your heart</TITLE><ARTIST>Bonnie Tyler</ARTIST><COUNTRY>UK</COUNTRY><COMPANY>CBS Records</COMPANY><PRICE>9.90</PRICE><YEAR>1988</YEAR></CD><CD><TITLE>Greatest Hits</TITLE><ARTIST>Dolly Parton</ARTIST><COUNTRY>USA</COUNTRY><COMPANY>RCA</COMPANY><PRICE>9.90</PRICE><YEAR>1982</YEAR></CD><CD><TITLE>Still got the blues</TITLE><ARTIST>Gary Moore</ARTIST><COUNTRY>UK</COUNTRY><COMPANY>Virgin records</COMPANY><PRICE>10.20</PRICE><YEAR>1990</YEAR></CD><CD><TITLE>Eros</TITLE><ARTIST>Eros Ramazzotti</ARTIST><COUNTRY>EU</COUNTRY><COMPANY>BMG</COMPANY><PRICE>9.90</PRICE><YEAR>1997</YEAR></CD><CD><TITLE>One night only</TITLE><ARTIST>Bee Gees</ARTIST><COUNTRY>UK</COUNTRY><COMPANY>Polydor</COMPANY><PRICE>10.90</PRICE><YEAR>1998</YEAR></CD><CD><TITLE>Sylvias Mother</TITLE><ARTIST>Dr.Hook</ARTIST><COUNTRY>UK</COUNTRY><COMPANY>CBS</COMPANY><PRICE>8.10</PRICE><YEAR>1973</YEAR></CD><CD><TITLE>Maggie May</TITLE><ARTIST>Rod Stewart</ARTIST><COUNTRY>UK</COUNTRY><COMPANY>Pickwick</COMPANY><PRICE>8.50</PRICE><YEAR>1990</YEAR></CD><CD><TITLE>Romanza</TITLE><ARTIST>Andrea Bocelli</ARTIST><COUNTRY>EU</COUNTRY><COMPANY>Polydor</COMPANY><PRICE>10.80</PRICE><YEAR>1996</YEAR></CD><CD><TITLE>When a man loves a woman</TITLE><ARTIST>Percy Sledge</ARTIST><COUNTRY>USA</COUNTRY><COMPANY>Atlantic</COMPANY><PRICE>8.70</PRICE><YEAR>1987</YEAR></CD><CD><TITLE>Black angel</TITLE><ARTIST>Savage Rose</ARTIST><COUNTRY>EU</COUNTRY><COMPANY>Mega</COMPANY><PRICE>10.90</PRICE><YEAR>1995</YEAR></CD><CD><TITLE>1999 Grammy Nominees</TITLE><ARTIST>Many</ARTIST><COUNTRY>USA</COUNTRY><COMPANY>Grammy</COMPANY><PRICE>10.20</PRICE><YEAR>1999</YEAR></CD><CD><TITLE>For the good times</TITLE><ARTIST>Kenny Rogers</ARTIST><COUNTRY>UK</COUNTRY><COMPANY>Mucik Master</COMPANY><PRICE>8.70</PRICE><YEAR>1995</YEAR></CD><CD><TITLE>Big Willie style</TITLE><ARTIST>Will Smith</ARTIST><COUNTRY>USA</COUNTRY><COMPANY>Columbia</COMPANY><PRICE>9.90</PRICE><YEAR>1997</YEAR></CD><CD><TITLE>Tupelo Honey</TITLE><ARTIST>Van Morrison</ARTIST><COUNTRY>UK</COUNTRY><COMPANY>Polydor</COMPANY><PRICE>8.20</PRICE><YEAR>1971</YEAR></CD><CD><TITLE>Soulsville</TITLE><ARTIST>Jorn Hoel</ARTIST><COUNTRY>Norway</COUNTRY><COMPANY>WEA</COMPANY><PRICE>7.90</PRICE><YEAR>1996</YEAR></CD><CD><TITLE>The very best of</TITLE><ARTIST>Cat Stevens</ARTIST><COUNTRY>UK</COUNTRY><COMPANY>Island</COMPANY><PRICE>8.90</PRICE><YEAR>1990</YEAR></CD><CD><TITLE>Stop</TITLE><ARTIST>Sam Brown</ARTIST><COUNTRY>UK</COUNTRY><COMPANY>A and M</COMPANY><PRICE>8.90</PRICE><YEAR>1988</YEAR></CD><CD><TITLE>Bridge of Spies</TITLE><ARTIST>T''Pau</ARTIST><COUNTRY>UK</COUNTRY><COMPANY>Siren</COMPANY><PRICE>7.90</PRICE><YEAR>1987</YEAR></CD><CD><TITLE>Private Dancer</TITLE><ARTIST>Tina Turner</ARTIST><COUNTRY>UK</COUNTRY><COMPANY>Capitol</COMPANY><PRICE>8.90</PRICE><YEAR>1983</YEAR></CD><CD><TITLE>Midt om natten</TITLE><ARTIST>Kim Larsen</ARTIST><COUNTRY>EU</COUNTRY><COMPANY>Medley</COMPANY><PRICE>7.80</PRICE><YEAR>1983</YEAR></CD><CD><TITLE>Pavarotti Gala Concert</TITLE><ARTIST>Luciano Pavarotti</ARTIST><COUNTRY>UK</COUNTRY><COMPANY>DECCA</COMPANY><PRICE>9.90</PRICE><YEAR>1991</YEAR></CD><CD><TITLE>The dock of the bay</TITLE><ARTIST>Otis Redding</ARTIST><COUNTRY>USA</COUNTRY><COMPANY>Atlantic</COMPANY><PRICE>7.90</PRICE><YEAR>1987</YEAR></CD><CD><TITLE>Picture book</TITLE><ARTIST>Simply Red</ARTIST><COUNTRY>EU</COUNTRY><COMPANY>Elektra</COMPANY><PRICE>7.20</PRICE><YEAR>1985</YEAR></CD><CD><TITLE>Red</TITLE><ARTIST>The Communards</ARTIST><COUNTRY>UK</COUNTRY><COMPANY>London</COMPANY><PRICE>7.80</PRICE><YEAR>1987</YEAR></CD><CD><TITLE>Unchain my heart</TITLE><ARTIST>Joe Cocker</ARTIST><COUNTRY>USA</COUNTRY><COMPANY>EMI</COMPANY><PRICE>8.20</PRICE><YEAR>1987</YEAR></CD></CATALOG>'));
  /
  COMMIT;




 SELECT P.xmlval.extract('//CATALOG/CD/TITLE/text()').GETSTRINGVAL AS CD

FROM   Xml_tab P;

非常欢迎任何解释。

Answer 1

这有点令人困惑，但你可以得到像这样的CD标题：

SELECT extract(value(b),'//TITLE/text()').getstringval() AS CD
FROM   xml_tab x, 
       TABLE(XMLSEQUENCE(extract(xmlval,'//CATALOG/CD'))) b

您可以先将xml转换为表格，然后使用EXTRACT函数获取值。

从XMLType列中提取值

1 个答案: