mysql-functions-examples.sql

#'\\' is a delimiter

select version() as 'mysql version';
drop function if exists test;
create function test (opcion int,num1 int, num2 int)
returns int
BEGIN
    declare res INT DEFAULT 0;
    declare mensaje TEXT;
    IF opcion=1 THEN
       #SELECT concat(num1, " + ", num2, " = ", num1 + num2) AS "suma";  # ERROR  Not allowed to return a result set from a function
       SELECT concat(num1, " + ", num2, " = ", num1 + num2) into mensaje; #meter el resultdo del select en una variable
       #CREATE TABLE t1 AS  SELECT concat(num1, " + ", num2, " = ", num1 + num2) ; #ERRORcrear tabla temporal y meter el resultado del select en ella
       #SELECT @MSG:= concat(num1, " + ", num2, " = ", num1 + num2) AS "suma";   #ERROR
        set res = num1 + num2;
        return res;
    END IF;
     
end \\

select concat("resultado de suma: ",test(1,5,5)) as resultado;