我在数据库中的xmltype列中存储了以下xml数据。
<TRNXS_DTL transactionSeq="1">
<TRNX_ITEM sequence="1" name="ERROR_CODE" value="2009"/>
<TRNX_ITEM sequence="2" name="ERROR_DESC" value="Data Not Found for given record id."/>
</TRNXS_DTL>
现在我尝试使用extract查询数据库,如下所示:
SELECT SRC_DSC_TXT as "TXT",
TYPE_CODE as "Code",
PID as "Participant ID",
SYS_ID as "System",
CHANEL as "Channel",
to_char(crt_ts,'MM/DD/YYYY HH24:MI:SS') as "Timestamp (MST)",
extract(TRX_DATA, '/TRNXS_DTL/TRNX_ITEM/text()') as "DETAILS"
FROM PARTICIPANT_DATA,
WHERE SRC_VAL_TXT =TYPE_CD;
但是当我运行上面的查询时,我在“详细信息”列下得到null,有什么想法吗?
答案 0 :(得分:1)
XML中的标记没有任何文本。它有三个属性:序列,名称和值。 因此,您的查询返回NULL。
请考虑以下示例。
create table myt(
type_code number,
trx_data xmltype
);
insert into myt values(101,
'<TRNXS_DTL transactionSeq="1">
<TRNX_ITEM sequence="1" name="ERROR_CODE" value="2009"/>
<TRNX_ITEM sequence="2" name="ERROR_DESC" value="Data Not Found for given record id."/>
</TRNXS_DTL>'
);
insert into myt values(102,
'<TRNXS_DTL transactionSeq="1">
<TRNX_ITEM sequence="1" name="ERROR_CODE" value="2010">NNN</TRNX_ITEM>
<TRNX_ITEM sequence="2" name="ERROR_DESC" value="Data Found for given record id.">OOO</TRNX_ITEM>
</TRNXS_DTL>'
);
SQL> select * from myt;
TYPE_CODE TRX_DATA
---------- -------------------------------------------------------------------------------------------------------------
101 <TRNXS_DTL transactionSeq="1">
<TRNX_ITEM sequence="1" name="ERROR_CODE" value="2009"/>
<TRNX_ITEM sequence="2" name="ERROR_DESC" value="Data Not Found for given record id."/>
</TRNXS_DTL>
102 <TRNXS_DTL transactionSeq="1">
<TRNX_ITEM sequence="1" name="ERROR_CODE" value="2010">NNN</TRNX_ITEM>
<TRNX_ITEM sequence="2" name="ERROR_DESC" value="Data Found for given record id.">OOO</TRNX_ITEM>
</TRNXS_DTL>
对于type_code 102,将NNN和OOO作为文本。
SQL> select type_code,
extract(trx_data, '/TRNXS_DTL/TRNX_ITEM/text()').getStringVal() as "DETAILS"
from myt;
TYPE_CODE DETAILS
---------- -------------
101
102 NNNOOO
你可以看到,它连接了两个标签的文本。
如果您在属性值之后,可以使用@
来指定属性。
SQL> select type_code,
extract(trx_data, '/TRNXS_DTL/TRNX_ITEM/@value').getStringVal() as "DETAILS"
from myt;
TYPE_CODE DETAILS
---------- ------------------------------------------
101 2009Data Not Found for given record id.
102 2010Data Found for given record id.
同样,正如您所看到的,文本是连接在一起的。
如果您希望它们位于不同的列中,则需要提供谓词以有条件地限制所选的节点。
SQL> select type_code,
extract(trx_data, '/TRNXS_DTL/TRNX_ITEM[@sequence="1"]/text()').getStringVal() as "DETAILS",
extract(trx_data, '/TRNXS_DTL/TRNX_ITEM[@sequence="2"]/text()').getStringVal() as "DETAILS2"
from myt;
TYPE_CODE DETAILS DETAILS2
---------- ------------------------ --------------
101
102 NNN OOO
SQL> select type_code,
extract(trx_data, '/TRNXS_DTL/TRNX_ITEM[@sequence="1"]/@value').getStringVal() as "DETAILS",
extract(trx_data, '/TRNXS_DTL/TRNX_ITEM[@sequence="2"]/@value').getStringVal() as "DETAILS2"
from myt;
TYPE_CODE DETAILS DETAILS2
---------- ------------------------ ------------------------------------------
101 2009 Data Not Found for given record id.
102 2010 Data Found for given record id.