Converting Long to Varchar2

Question

I am trying to insert into varchar2 column from a long column. here is the below example, TEXT.TEXT_COL = VARCHAR2(4000) and NOTE.TEXT_NOTE = LONG.

Answer 1

It looks like Oracle internally converts LONG to something else (probably CLOB) when you select LONG in FOR loop. I did not find any explanations in Oracle documentation, but this works

BEGIN
  FOR V IN (SELECT ROWID,TEXT_NOTE FROM NOTE)
  LOOP
    INSERT INTO TEXT VALUES(V.ROWID, SUBSTR(V.TEXT_NOTE, 1, 4000) );   
  END LOOP;
  COMMIT;
END;

This is an example how to copy all views from another schema to your schema

BEGIN
  FOR V IN (SELECT VIEW_NAME, TEXT_LENGTH, TEXT FROM ALL_VIEWS WHERE OWNER = 'PROD')
  LOOP
    EXECUTE IMMEDIATE 'CREATE OR REPLACE FORCE VIEW '||V.VIEW_NAME||' AS '||SUBSTR(V.TEXT, 1, V.TEXT_LENGTH);
    DBMS_OUTPUT.PUT_LINE('View '||V.VIEW_NAME||' created');
  END LOOP;
END;

For some reason it only works for FOR loop and does not work if you use WITH or select from another query

INSERT INTO TEXT
WITH V AS(SELECT ROWID ROW_ID,TEXT_NOTE FROM NOTE)
SELECT V.ROW_ID, SUBSTR(V.TEXT_NOTE, 1, 4000) FROM V; 

INSERT INTO TEXT
SELECT ROW_ID, SUBSTR(TEXT_NOTE, 1, 4000) 
FROM (SELECT ROWID ROW_ID,TEXT_NOTE FROM NOTE); 

Both inserts raise the same error

ORA-00932: inconsistent datatypes: expected CHAR got LONG