Function or pseudo-column 'DECODE' may be used inside a SQL statement only

Question

Hi everyone!
I got the error in the subject concernig the follow piece of sql code
+ v_str_sql_body :=
v_str_sql_body || ' and cod_entita ='
|| decode(cur.cod_entita_a,str_all,cur_ent.cod_entita,cur.cod_entita_a);
execute immediate v_str_sql_body; +
I can't understand what's the problem with it.
Can anyone help me to find the error?
Thank you in advance!
Samuel
Edited by: 996508 on 27-mar-2013 5.29

Answer 1

Hi, Samuel,
Welcome to the forum!
996508 wrote:
Hi everyone!
I got the error in the subject concernig the follow piece of sql code
+ v_str_sql_body :=
v_str_sql_body || ' and cod_entita ='
|| decode(cur.cod_entita_a,str_all,cur_ent.cod_entita,cur.cod_entita_a);
execute immediate v_str_sql_body; +
I can't understand what's the problem with it.Sorry, I can't understand what you're trying to do.
Whenever you have a problem, post a complete script that people can run to re-create the problem and test their ideas. Include your complete PL/SQL code (if the problem involves PL/SQL) including code to call your procedure, a little sample data (CREATE TABLE and INSERT statements) for any tables involved, and the results you want the given sample data.
Always say which version of Oracle you have (e.g., 11.2.0.3.0).
See the forum FAQ {message:id=9360003}
Can anyone help me to find the error?As the error message says, you can only use DECODE in a SQL statement. That is:
v_str_body := v_str_body
        || ' and cod_entita = '
        || DECODE (...);is always an error, no matter what ... stands for.
Perhaps you meant to have the DECODE inside the string literal.
If not, then (depending on your version) you can use CASE instead of DECODE:
v_str_body := v_str_body
        || ' and cod_entita = '
        || CASE  cur.cod_entita_a
                 WHEN  str_all  THEN  cur_ent.cod_entita
                             ELSE  cur.cod_entita_a
           END;Anything that DECODE can do, CASE can do, too.
DECODE is sometimes a little simpler than CASE to use, but only a little. It is never faster than CASE.
CASE is sometimes much, much simpler to use than DECODE, and sometimes much faster, too.
I won't say never use DECODE; but I will say rarely use DECODE. Use CASE instead, unless you have a specific reason why DECODE is better in that particular situation.
In PL/SQL, you can also use IF ... THEN ... ELSE in places where you might want to use DECODE or CASE.
For example:
v_str_body := v_str_body
        || ' and cod_entita = ';
IF  cur.cod_entita_a = str_all
THEN
    v_str_body := v_str_body
                || cur_ent.cod_entita;
ELSE
    v_str_body := v_str_body
                || cur.cod_entita_a;
END IF;Edited by: Frank Kulash on Mar 27, 2013 5:59 PM
Added IF ... THEN ... ELSE example.