XMLtable with Oracle 11g

问题:

Here is a sample table:

create table xmltemp (mydoc xmltype) 

Here is a small xml doc for it:

insert into xmltemp values ( xmltype ('CanadaUSWashingtonOregon ') )   

Notice that Canada does not have a 'states' element but the US does. I'm trying to get these query results (order and formatting is not important):

Canada, US,Washington US,Oregon 

When I execute this, I see both Canada and the US in the result:

select countryname from xmltemp, xmltable('/countries/country' passing mydoc    columns countryname varchar2(10) path 'name')  

When I do this, I get both the states:

select statename from xmltemp, xmltable('/countries/country/states/state/name' passing mydoc    columns statename   varchar2(20) path '.') c 

I tried this to get both country and states, but it seems oracle does not like the '..' syntax:

select statename from xmltemp, xmltable('/countries/country/states/state/name' passing mydoc    columns statename   varchar2(20) path '.',            countryname varchar2(20) path '../../../name') c 

Heres the error:

ORA-19110: unsupported XQuery expression 

When I try this, I get the 'multi-item' error because of the two states:

select countryname, statename from xmltemp, xmltable('/countries/country' passing mydoc    columns countryname varchar2(10) path 'name',            statename   varchar2(20) path 'states/state/name') c 

Here is that error:

ORA-19279: XPTY0004 - XQuery dynamic type mismatch: expected singleton  sequence - got multi-item sequence 

What's a query that will get me my desired output of:

Canada, US,Washington US,Oregon 

Thanks

回答1:

Try this:

select      X.COUNTRYNAME, Y.STATENAME from        XMLTEMP            ,xmltable('/countries/country'                      passing MYDOC                      columns COUNTRYNAME varchar2(20) path './name',                               STATES xmltype path './states') X,             xmltable('/states/state/name' passing X.STATES                      columns STATENAME varchar2(20) path '.') (+) Y 

Because you have multiple states you should join to another xml table. As some countries have no states then it needs to be a left outer join. I'm using the old method of (+) as I'm trying this on 10g and it seems there's a problem using left outer join in 10g but apparently it should be fine in 11g.

文章来源: XMLtable with Oracle 11g