Problem with comparion of clobs in stored procedure

Question

Hi ,
i have a stored procedure which involves a clob variable and a string comparison.
Below is my procedure
CREATE OR REPLACE PROCEDURE TEMP_SP (
empId IN VARCHAR2)
IS
tempStr CLOB :='Hello';
finalStr CLOB :='world';
BEGIN
IF finalStr = 'xxx' THEN
tempStr := ' ';
finalStr := finalStr || empId;
END IF;
IF trim(finalSqltoCur) IS NOT NULL AND tempStr <> ' ' THEN
finalStr := finalStr || ' and ' || tempStr;
ELSE
finalStr := finalStr || tempStr;
END IF;
dbms_output.put_line('=========final string value======' || finalStr);
END TEMP_SP;
I would like to know why it goes to the else block as tempStr <> ' ' will be true
and trim(finalSqltoCur) IS NOT NULL also results as true.
It would be great if some one could help me with this.
Regards
Shyam

Answer 1

> trim(finalStr) IS NOT NULL AND tempStr <> ' '
And this is (TRUE AND TRUE) and evaluates to TRUE - which means the ELSE block will not be executed,
SQL> declare
2 empId number := 123;
3 tempStr CLOB :='Hello';
4 finalStr CLOB :='world';
5 begin
6 IF finalStr = 'xxx' THEN
7 tempStr := ' ';
8 finalStr := finalStr || empId;
9 END IF;
10
11
12 IF trim(finalStr) IS NOT NULL AND tempStr <> ' ' THEN
13 finalStr := finalStr || ' and ' || tempStr;
14 ELSE
15 finalStr := finalStr || tempStr;
16 END IF;
17
18 DBMS_OUTPUT.put_line('=========final string value======' || finalStr);
19 end;
20 /
=========final string value======world and Hello
PL/SQL procedure successfully completed.
SQL>
Tested on Oracle 10.2.0.1.