String Aggregation - ORA-01489

Question

Hi, I am getting ORA-01489 for the following query. Basically, I am performing string aggregation:
SELECT LTRIM(REPLACE(sys_connect_by_path(expression, '::'), '::', ','),',')
INTO clob_variable
FROM (SELECT * FROM tb_metadata_detail WHERE performance_metadata_id = 2) TMD
WHERE connect_by_isleaf = 1
CONNECT BY performance_metadata_detail_id = PRIOR
performance_metadata_detail_id + 1
START WITH performance_metadata_detail_id = 1;
I heard to_clob can help. but where to put it?

Answer 1

I've got an idea:
Why don't you post some sample data which reproduce your problem? Instead of NO ROWS SELECTED
SQL> CREATE TABLE TB_METADATA_DETAIL
  2  (
  3  PERFORMANCE_METADATA_ID NUMBER,
  4  PERFORMANCE_METADATA_DETAIL_ID NUMBER,
  5  EXPRESSION CLOB,
  6  TARGET_COLUMN VARCHAR2(30 )
  7  );
Table created.
SQL>
SQL>
SQL> insert into TB_METADATA_DETAIL values (2, 1, 'SYSTEM_DATE', 'SYSTEM_DATE');
1 row created.
SQL> insert into TB_METADATA_DETAIL values (2, 2, 'LOAD_DATE'  , 'SYSDATE'    );
1 row created.
SQL>
SQL> commit;
Commit complete.
SQL>
SQL> SELECT LTRIM(REPLACE(sys_connect_by_path(expression, '::'), '::', ','),',')
  2  --INTO clob_variable
  3  FROM (SELECT * FROM tb_metadata_detail WHERE performance_metadata_id = 2) TMD
  4  WHERE connect_by_isleaf = 1
  5  CONNECT BY performance_metadata_detail_id = PRIOR performance_metadata_detail_id + 1
  6  START WITH performance_metadata_detail_id = 1;
no rows selected