ORA-00900: invalid SQL statement for Oracle Procedure - oracle

Question

I am trying to execute my below procedure but kept getting error (ORA-00900: invalid SQL statement)
CREATE OR REPLACE PROCEDURE RESETUSERSESSION (run IN VARCHAR2)
IS
cursor usersessiondetail_cur IS
SELECT usd.CLIENTID,usd.OPERID,usd.REGISTER,usd.MACHINE_ID,usd.SESSIONNUMBER
FROM cashiering_dev.CSH_USER usr, cashiering_dev.CSH_USERSESSIONDETAIL usd
WHERE usr.clientid = usd.clientid
AND usr.operid = usd.operid
AND usr.register = usd.register
AND usr.machine_id = usd.machine_id
AND usr.sessionnumber = usd.sessionnumber
AND usr.Machine_ID = 'basrytest'
AND usd.LOGOFFDATETIME IS NULL;
BEGIN
OPEN usersessiondetail_cur;
FOR vItems in usersessiondetail_cur
LOOP
EXECUTE IMMEDIATE 'UPDATE csh_UserSessionDetail
SET ClientID =vItems.CLIENTID
WHERE ClientID =vItems.CLIENTID
AND OperID =vItems.OPERID
AND Register =vItems.REGISTER
AND Machine_ID =vItems.MACHINE_ID
AND SessionNumber =vItems.SESSIONNUMBER';
END LOOP;
CLOSE usersessiondetail_cur;
END;

Answer 1

Your SQL is invalid because the cursor projection names are not in scope when the dynamic SQL string is executed. You need to use placeholders like this:
FOR vItems in usersessiondetail_cur
LOOP
EXECUTE IMMEDIATE 'UPDATE csh_UserSessionDetail
SET ClientID = :p1
WHERE ClientID = :p2
AND OperID = :p3
AND Register = :p4
AND Machine_ID = :p5
AND SessionNumber = :p6'
using vItems.CLIENTID
, vItems.CLIENTID
, vItems.OPERID
, Items.REGISTER
, vItems.MACHINE_ID
, vItems.SESSIONNUMBER;
END LOOP;
Your dynamic code is not an anonymous PL/SQL block or a CALL statement so parameters are passed by position not name, which means you must pass vItems.CLIENTID twice. Find out more.
Other observations
First and foremost, there is absolutely no need to implement dynamic execution for this SQL.
The OPEN and CLOSE cursor statements are not used with a FOR cursor loop.
You do not need an explicit cursor declaration for this query.
The row-by-agonising row UPDATE with a cursor loop is bad practice and needlessly inefficient compared to set-based UPDATE statement.
Your procedure doesn't use the run parameter ...
... but the cursor does have a hardcoded string for MACHINE_ID.
Lastly, the UPDATE statement doesn't actually change the state of the table, because it sets CLIENT_ID = CLIENT_ID, so the whole procedure is pointless.
Apart from that, everything is fine.
I assume you're writing this as a test for understanding how to use dynamic SQL rather than as an implementation of business logic. But even if it is a test it is better to write a proper piece of code which does something. Especially when you're sharing the code with others on StackOverflow. Posting code with so many issues is distracting because potential respondents don't know which to tackle.

Answer 2

A much simpler approach with just FOR loop. We dont require to Open Close cursor in this case as this is internally handled by Oracle. Also I do not understand the need of updating Client ID again. If we are selecting the Client ID in where Clause there is no significance of Updating. Anyhow Enjoy :)
CREATE OR REPLACE
PROCEDURE RESETUSERSESSION(
run IN VARCHAR2)
AS
BEGIN
FOR vItems IN
(SELECT usd.CLIENTID,
usd.OPERID,
usd.REGISTER,
usd.MACHINE_ID,
usd.SESSIONNUMBER
FROM cashiering_dev.CSH_USER usr,
cashiering_dev.CSH_USERSESSIONDETAIL usd
WHERE usr.clientid = usd.clientid
AND usr.operid = usd.operid
AND usr.register = usd.register
AND usr.machine_id = usd.machine_id
AND usr.sessionnumber = usd.sessionnumber
AND usr.machine_id = 'basrytest'
AND usd.LOGOFFDATETIME IS NULL
)
LOOP
UPDATE csh_UserSessionDetail
SET ClientID =vItems.CLIENTID
WHERE ClientID =vItems.CLIENTID
AND OperID =vItems.OPERID
AND Register =vItems.REGISTER
AND Machine_ID =vItems.MACHINE_ID
AND SessionNumber =vItems.SESSIONNUMBER;
END LOOP;
END;
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