PL SQL - convert a numerical value into varchar (percent)

I 开发者_Go百科have a query that uses the outputs(R1,R2) of two sub queries in order to divide them:

select a.R1/b.R2*100.0 as Result
from
(query1) a,
(query2) b

The division's output is a (decimal) number as well as the R1,R2 outputs.

I want to add to the Result the '%' sign, (i.e 10,75 %), but using a solution like the below one, returns an error 01722=invalid number

select cast(cast(a.R1/b.R2*100.0 as decimal(10,2)) as varchar(10)) + '%' as Result
from
(query1) a,
(query2) b

Welcome!

Replace the addition operator '+' with the SQL-Pl/sql concatenation operator: '||'.

We can't use character literals directly in number format models like in Datetime conversion.

SQL Concatenation operator

PL/SQL Concatenation operator

Number format models

Examples:

select cast(round(10.75, 2) as varchar(10)) || '%' as result
from   dual

select to_char(round(1234567890.29, 2),'9G999G999G999D99' ) || '%' as result
from   dual

PS. The route is always the same:

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