Problem with INSTR and SUBSTR ???

Hello,

SELECT lastname, INSTR(lastname, 'O', 2, 1) from data;

The above query can work well.

But, is it possible to use INSTR not with a query ?

For instance,

declare

    str0 varchar2(30);
begin

    str0 := INSTR('abcdefghi', 'cd', 1, 1); end;

I tried the above statements, it seems that INSTR in that situation can't work.

So, if I want to use INSTR or SUBSTR in a store procedure but not in a query,
how to do it ?

Would you please to give me a simple example ???

Best regards,
Eric
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 _( /_  | _   Chow Hoi Ka, Eric                    _ |  _) )_


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