是否可以创建一个for循环，以一个SQL过程提供PL / SQL中的结果集？

Question

In an attempt to feed the result (owner, object_name) of a query into DBMS_STATS I've tried the following PL/SQL fragment:

DECLARE
  CCLOB  VARCHAR2(500);
  BEGIN
   FOR rec IN (
            select o.owner own,o.object_name obn
            from sys.col_group_usage$ cg,dba_objects o
             where cg.obj#=o.object_id
             group by owner,object_name
               )
   LOOP
      DBMS_OUTPUT.put_line (rec.own||' '||rec.obn);
      SELECT dbms_stats.report_col_usage(ownname =>'''rec.own''', tabname =>'''rec.obn''') into CCLOB from dual;
      DBMS_OUTPUT.PUT_LINE(CCLOB);
   END LOOP;
END;
/

but the result is:

DWI DWATOBP
ORA-20001: 'REC.OWN' is an invalid identifier

################SNPI#################

AGUN RDC
ORA-20001: 'REC.OWN' is an invalid identifier

PL/SQL procedure successfully completed.

Some variations on the code with their errors:

a) with no quotes:

SELECT dbms_stats.report_col_usage(ownname =>rec.own, tabname =>rec.obn) into CCLOB from dual;

DWI DWATOBP
DECLARE
*
ERROR at line 1:
ORA-06502: PL/SQL: numeric or value error
ORA-06512: at line 14

b) with 1 single quote:

SELECT dbms_stats.report_col_usage(ownname =>'rec.own', tabname =>'rec.obn') into CCLOB from dual;

DWI DWATOBP
ORA-20001: REC.OWN is an invalid identifier

c) with 2 single quotes:

SELECT dbms_stats.report_col_usage(ownname =>''rec.own'', tabname =>''rec.obn'') into CCLOB from dual;

ERROR at line 14:
ORA-06550: line 14, column 54:
PL/SQL: ORA-00907: missing right parenthesis
ORA-06550: line 14, column 7:
PL/SQL: SQL Statement ignored

Answer 1

By passing the parameters in as '''rec.own''' and '''rec.obn''', you're actually passing in the strings: 'rec.own' and 'rec.obn'. Neither of which are valid identifier names!

Remove the single quotes, and it should work.

ETA: Also, change the variable CCLOB to be CLOB datatype, as dbms_stats.report_col_usage returns a CLOB.