A very basic sql xml question..

Question

I want to print only two rows group by grup number so there are only two group numbers
0 and 1...
so 0 group should have two items...
Elapsed: 00:00:00.01
15:15:55 SQL>
15:15:56 SQL> l
  1  with data as
  2    (select 0 as grp,'A' item_name , 'XX' Item_desc from dual
  3     union
  4      select 0 ,'B'  , 'XY'  from dual
  5      union
  6      select 1 ,'B'  , 'Y'  from dual
  7       )
  8  select xmlelement(name "grp",
  9            xmlforest(grp  "item_name",item_name)
10            )
11*  from data
15:15:57 SQL> /
XMLELEMENT(NAME"GRP",XMLFOREST(GRP"ITEM_NAME",ITEM_NAME))
<grp><item_name>0</item_name><ITEM_NAME>A</ITEM_NAME></grp>
<grp><item_name>0</item_name><ITEM_NAME>B</ITEM_NAME></grp>
<grp><item_name>1</item_name><ITEM_NAME>B</ITEM_NAME></grp>
Elapsed: 00:00:00.01

Answer 1

Hi,
You should use XMLAGG, to get everything into a single XML element. And DON'T use extract()!!
Something like:
SQL> declare
   xml   xmltype;
begin
  with data as
    (select 0 grp, 'g1' grp_name, 'A' item_name, 'XX' item_desc from dual union all
     select 0    ,  'g1' grp_name,'B'          , 'XY'           from dual union all
     select 0    ,  'g2' grp_name,'B'          , 'XY'           from dual union all
     select 0    ,  'g3' grp_name,'B'          , 'XY'           from dual union all
     select 1    ,  'g1' grp_name,'B'          , 'Y'            from dual)
-- end of test data    
     select xmlagg(xmlelement("GRP"
                             ,xmlagg(xmlelement("ITEM_NAME", item_name))
                             ,xmlagg(xmlelement("item_desc", item_desc))))
       into xml
       from data
   group by grp, grp_name, item_name;
   dbms_output.put_line(dbms_lob.getlength(xml.getclobval()));
end;
299
PL/SQL procedure successfully completed.Regards
Peter