oracle function函数-蒲公英云

oracle function函数

函数调用限制
1、SQL语句中只能调用存储函数(服务器端),而不能调用客户端的函数
2、SQL只能调用带有输入参数,不能带有输出,输入输出函数
3、SQL不能使用PL/SQL的特有数据类型(boolean,table,record等)
4、SQL语句中调用的函数不能包含INSERT,UPDATE和DELETE语句

1.function函数的语法如下：

[sql] view plain copy

createorreplacefunction function_name (
argu1 [mode1] datatype1, --定义参数变量
argu2 [mode2] datatype2 --定义参数变量
) return datatype --定义返回的数据类型
is
begin
end;

执行：

[sql] view plain copy

var v1 varchar2(100)
exec =function_name

2.不带任何参数的定义

[sql] view plain copy

createorreplacefunction get_user
return varchar2
is
Result varchar2(50); --定义变量
begin
select username into Result from user_users;
return(Result); --返回值
end get_user;

3.带有in参数的

[sql] view plain copy

createorreplacefunction get_sal(
empname in varchar2
) return number
is
Result number;
begin
select sal into Result from emp where ename=empname;
return(Result);
end;

执行：

[sql] view plain copy

SQL> var sal number
SQL> exec =get_sal(‘scott’);

4.带out参数的

[sql] view plain copy

createorreplacefunction get_info(
e_name varchar2,
job out varchar2
) return number
Is
Result number;
begin
select sal,job into Result,job from emp where ename=e_name;
return(Result);
end;

执行：

[sql] view plain copy

SQL> var job varchar2(20)
SQL> var dname varchar2(20)
SQL> exec =get_info(‘SCOTT’,:job)

5.带in out参数的

6.函数调用举例

[sql] view plain copy

createorreplacefunction f_sys_getseqid(
v_seqname IN VARCHAR2,
v_provincecode IN VARCHAR2 --省编码
) return Varchar2
IS
iv_date VARCHAR2(8);
iv_seqname VARCHAR2(50);
iv_sqlstr VARCHAR2(200);
iv_seq VARCHAR2(8);
iv_seqid VARCHAR2(16);
BEGIN
iv_seqname := LOWER(TRIM(v_seqname));
iv_sqlstr := ‘SELECT ‘||iv_seqname||’.nextval FROM DUAL’;
EXECUTE IMMEDIATE iv_sqlstr INTO iv_seq;--执行动态的sql语句，执行相似的一组语句
IF v_seqname = ‘SEQ_FUNCROLE_ID’THEN
iv_seqid:= ‘ESS’ || LPAD(iv_seq,5,’0’);
ELSE
SELECT substrb(v_provincecode,1,2)||TO_CHAR(SYSDATE,’yymmdd’) INTO iv_date FROM DUAL;
iv_seqid:= iv_date || LPAD(iv_seq,8,’0’);
END IF;
RETURN iv_seqid;
EXCEPTION
WHEN OTHERS THEN
RETURNNULL;
END;