Oracle function语法

2018-3-30 遇到需要使用SQL方法拼接字符串的情况，就研究了一下SQL简单的方法应用

       --定义入参数[参数名 in 参数类型]
 create or replace function p_gettype(se_type in varchar2) 
       --定义返回类型
	  return   varchar2 
is
       v_calling_type        varchar2(45);
       v_called_type         varchar2(45);
       v_tr_in            varchar2(45);
       v_tr_out           varchar2(45);
       v_sett_name           varchar2(90);
begin
  --查出v_calling_type
  select call_type_name into v_calling_type from uparam.settle_a_def 
  where call_type = substr(se_type,1,2);
  --查出v_called_type
  select call_type_name into v_called_type from uparam.settle_a_def 
  where call_type = substr(se_type,3,2);
  --查出v_tr_in
  select tr_type_name into v_tr_in from uparam.tr_b_def 
  where tr_type = substr(se_type,5,2);
  --查出v_tr_out
  select tr_type_name into v_tr_out from uparam.tr_b_def 
  where tr_type = substr(se_type,7,2);
  --返回字符串 calling_type(tr_in)->called_type||(tr_out);
  v_sett_name := v_calling_type ||'('|| v_tr_in||')->'||v_called_type||'('|| v_tr_out||')';
  return v_sett_name;
exception
  when others then
  return null;
end p_gettype;