IS_INTEGER()判断是数字、字符串

create or replace function IS_INTEGER(VAR_VALUE IN VARCHAR) return NUMBER is
Result NUMBER;
begin
Result := TO_NUMBER(VAR_VALUE);
return Result;
EXCEPTION
WHEN others THEN
begin
return - 1;
end;
end IS_INTEGER;

--字符串的返回负数-1，数字的则是不等于-1