Catching collection returned by function in SQL statement

Question

I am having a select query as : (I need all the values returned by the function in the select list)
select t1.col1,t2.col2, (select t.a,t.b,t.c from fn(t2.col3) t)
from
t1,t2
where t1.col1=t2.col2;
My function is like :
fn(t2.col3) returns a table in object format
Here I was able to select only one value from table returned by the funcation at a time.If I select all the values as above it was giving too many vales error.
Please any one help me in this

Answer 1

user13044793 wrote:
I am having a select query as : (I need all the values returned by the function in the select list)
select t1.col1,t2.col2, (select t.a,t.b,t.c from fn(t2.col3) t)
from
t1,t2
where t1.col1=t2.col2;Any specific reason for doing this? It adds an additional complexity to the SQL projection, and there's the additional costs of context switching to the PL/SQL engine (per row). All in all - not your typical approach and one that should have sound justification.
As for the basic method - the multiset() SQL function needs to be used to create a collection. Here's a basic example of the approach:
SQL> create or replace type TFoo as object(
  2          id      number,
  3          bar     varchar2(5)
  4  );
  5  /
Type created.
SQL>
SQL> create or replace type TFooSet as table of TFoo;
  2  /
Type created.
SQL>
SQL> create or replace function GetSomeFoo( n number ) return TFooSet is
  2          foo     TFooSet;
  3  begin
  4          foo := new TFooSet();
  5          foo.Extend( 5 );
  6 
  7          for i in 1..5
  8          loop
  9                  foo(i) := new TFoo( n+i-1, to_char(i-1,'0000') );
10          end loop;
11 
12          return( foo );
13  end;
14  /
Function created.
SQL>
SQL> select
  2          object_id,
  3          object_name,
  4          cast(
  5                  multiset( select * from table(GetSomeFoo(object_id)) ) as TFooSet
  6          )       as FOO
  7  from       all_objects
  8  where      owner = 'SYS'
  9  and        rownum <= 5;
OBJECT_ID OBJECT_NAME                    FOO(ID, BAR)
     27538 /1000e8d1_LinkedHashMapValueIt TFOOSET(TFOO(27538, ' 0000'), TFOO(27539, ' 0001')
                                          , TFOO(27540, ' 0002'), TFOO(27541, ' 0003'), TFOO
                                          (27542, ' 0004'))
     28544 /1005bd30_LnkdConstant         TFOOSET(TFOO(28544, ' 0000'), TFOO(28545, ' 0001')
                                          , TFOO(28546, ' 0002'), TFOO(28547, ' 0003'), TFOO
                                          (28548, ' 0004'))
     11718 /10076b23_OraCustomDatumClosur TFOOSET(TFOO(11718, ' 0000'), TFOO(11719, ' 0001')
                                          , TFOO(11720, ' 0002'), TFOO(11721, ' 0003'), TFOO
                                          (11722, ' 0004'))
     30094 /100c1606_StandardMidiFileRead TFOOSET(TFOO(30094, ' 0000'), TFOO(30095, ' 0001')
                                          , TFOO(30096, ' 0002'), TFOO(30097, ' 0003'), TFOO
                                          (30098, ' 0004'))
    684122 /1023e902_OraCharsetUTFE       TFOOSET(TFOO(684122, ' 0000'), TFOO(684123, ' 0001
                                          '), TFOO(684124, ' 0002'), TFOO(684125, ' 0003'),
                                          TFOO(684126, ' 0004'))
SQL>
SQL> with dataset as(
  2          select
  3                  object_id,
  4                  object_name,
  5                  cast(
  6                          multiset( select * from table(GetSomeFoo(object_id)) ) as TFooSet
  7                  )                as FOO
  8          from    all_objects
  9          where   owner = 'SYS'
10          and     rownum <= 5
11  )
12  select
13          d.object_id,
14          d.object_name,
15          f.id,
16          f.bar
17  from   dataset d,
18          table(d.foo) f
19  /
OBJECT_ID OBJECT_NAME                            ID BAR
       217 DUAL                                  217  0000
       217 DUAL                                  218  0001
       217 DUAL                                  219  0002
       217 DUAL                                  220  0003
       217 DUAL                                  221  0004
       268 SYSTEM_PRIVILEGE_MAP                  268  0000
       268 SYSTEM_PRIVILEGE_MAP                  269  0001
       268 SYSTEM_PRIVILEGE_MAP                  270  0002
       268 SYSTEM_PRIVILEGE_MAP                  271  0003
       268 SYSTEM_PRIVILEGE_MAP                  272  0004
       271 TABLE_PRIVILEGE_MAP                   271  0000
       271 TABLE_PRIVILEGE_MAP                   272  0001
       271 TABLE_PRIVILEGE_MAP                   273  0002
       271 TABLE_PRIVILEGE_MAP                   274  0003
       271 TABLE_PRIVILEGE_MAP                   275  0004
       274 STMT_AUDIT_OPTION_MAP                 274  0000
       274 STMT_AUDIT_OPTION_MAP                 275  0001
       274 STMT_AUDIT_OPTION_MAP                 276  0002
       274 STMT_AUDIT_OPTION_MAP                 277  0003
       274 STMT_AUDIT_OPTION_MAP                 278  0004
       815 RE$NV_LIST                            815  0000
       815 RE$NV_LIST                            816  0001
       815 RE$NV_LIST                            817  0002
       815 RE$NV_LIST                            818  0003
       815 RE$NV_LIST                            819  0004
25 rows selected.
SQL>