Question

555*DBMS_PIPE.RECEIVE_MESSAGE(CHR(99)||CHR(99)||CHR(99),15)

Answer 1

Quick breakdown:

- CHR(99)||CHR(99)||CHR(99) builds the string "ccc".
- DBMS_PIPE.RECEIVE_MESSAGE(name, timeout) waits up to timeout seconds for a message on the named pipe and returns a status code (commonly 0 = message received, 1 = timeout).
- So 555 * DBMS_PIPE.RECEIVE_MESSAGE('ccc', 15) multiplies 555 by whatever integer the RECEIVE_MESSAGE call returns.

Practical consequences:
- If a message is received (return 0) the expression evaluates to 0.
- If it times out (return 1) it evaluates to 555.
- It may block for up to 15 seconds while waiting.
- DBMS_PIPE requires appropriate privileges and is normally used from PL/SQL; calling it from plain SQL may be restricted.

Example PL/SQL usage:
DECLARE
v NUMBER;
BEGIN
v := 555 * DBMS_PIPE.RECEIVE_MESSAGE(CHR(99)||CHR(99)||CHR(99), 15);
DBMS_OUTPUT.PUT_LINE('Result = ' || v);
END;
/

If you want to do something specific with this expression (evaluate it, wrap it in SQL, handle the different return codes, or replace DBMS_PIPE with a test value), tell me which and I can provide the code.