Error When Prompting for Substitution Variable

Question

Hi - I'm receiving an error when I try to run the following using the substitution variable - but only when I enter a string; when I enter a numeric value it runs fine.
DECLARE
    l_SCR_Info            VARCHAR2(50) := '''SCR'||&SCR_NUM||'-'||'''';
begin
dbms_output.put_line(l_SCR_Info);
end;Here is the error I receive when I supply a string value when prompted:
ORA-06550: line 3, column 52:
PLS-00201: identifier 'AB' must be declared
ORA-06550: line 3, column 27:
PL/SQL: Item ignored
ORA-06550: line 10, column 22:
PLS-00320: the declaration of the type of this expression is incomplete or malformed
ORA-06550: line 10, column 1:
PL/SQL: Statement ignoredCan anyone shed some light on what I'm missing here?
Thanks!
Christine

Answer 1

Hi,
It looks like you just want one string there:
l_SCR_Info            VARCHAR2(50) := '''SCR&SCR_NUM-''';Remeber how substitution variables work: SQL*Plus replaces them with values before sending the code to the back end to be compiled.
If you give a value like AB for the variable, the code you posted is equivalent to:
     l_SCR_Info            VARCHAR2(50) := '''SCR'|| AB ||'-'||'''';by the time it reaches the compiler. AB is not inside quotes, so the compiler looks for a variable or function called AB.
If you gave a number:
     l_SCR_Info            VARCHAR2(50) := '''SCR'|| 123 ||'-'||'''';there's no problem; the compile knows what the literal number 123 is.