1、语法
LAG (value_expression [,offset] [,default]) OVER ([query_partition_clause] order_by_clause)
LEAD (value_expression [,offset] [,default]) OVER ([query_partition_clause] order_by_clause)

2、说明
1）lag 和lead 可以 获取结果集中，按一定排序所排列的当前行的上下相邻若干offset 的某个行的某个列(不用结果集的自关联）
2）lag 和lead 有三个参数，第一个参数是列名，第二个参数是偏移的offset，第三个参数是超出记录窗口时的默认值
3）lag ，lead 分别是向前，向后

3、准备试验环境

CREATE TABLE t(t_NAME VARCHAR2(10),t_order NUMBER);
INSERT INTO t VALUES('aaaa',1);
INSERT INTO t VALUES('bbbb',2);
INSERT INTO t VALUES('cccc',3);
INSERT INTO t VALUES('dddd',6);
INSERT INTO t VALUES('eeee',4);
INSERT INTO t VALUES('ffff',5);
SELECT * FROM t;
T_NAME        T_ORDER
---------- ----------
aaaa                1
bbbb                2
cccc                3
dddd                6
eeee                4
ffff                5
6 rows selected

4、测试

SELECT T_ORDER,
LAG(T_NAME, 1,'lag_fei') OVER(ORDER BY T_ORDER) "LAG",
T_NAME,
LEAD(T_NAME, 1,'lead_fei') OVER(ORDER BY T_ORDER)"LEAD"
FROM T
ORDER BY T_ORDER;

T_ORDER LAG        T_NAME     LEAD
---------- ---------- ---------- ----------
1 lag_fei    aaaa       bbbb
2 aaaa       bbbb       cccc
3 bbbb       cccc       eeee
4 cccc       eeee       ffff
5 eeee       ffff       dddd
6 ffff       dddd       lead_fei
6 rows selected

1、创建表

desc test_rollup;
Name        Type         Nullable Default Comments 
----------- ------------ -------- ------- -------- 
TYPE_NAME   VARCHAR2(10) Y                         
TYPE_VALUE  NUMBER       Y                         
TYPE_NAME2  VARCHAR2(10) Y                         
TYPE_VALUE2 NUMBER       Y  

2、插入数据

select * from test_rollup;
 
TYPE_NAME  TYPE_VALUE TYPE_NAME2 TYPE_VALUE2
---------- ---------- ---------- -----------
a                 123 t1                 120
a                 423 t2                 200
a                 523 t1                 555
b                 223 x1                 504
b                 283 x2                 484
c                 103 y1                 333
c                 843 y2                 984
c                 899 y2                 151
c                 100 y2                 150
d                 204 s1                 606
 
10 rows selected

3、使用grouping_id查询结果

 select type_name,
        type_name2,
        decode(grouping_id(type_name), 0, type_name, '总计')g_type,
        decode(grouping_id(type_name2), 0, type_name2, decode(grouping_id(type_name),0,'小计','总计'))g2_type,
        grouping_id(type_name, type_name2)gg_type,
        sum(type_value),
        sum(type_value2)
   from test_rollup
  group by rollup(type_name, type_name2);
TYPE_NAME  TYPE_NAME2 G_TYPE     G2_TYPE       GG_TYPE SUM(TYPE_VALUE) SUM(TYPE_VALUE2)
---------- ---------- ---------- ---------- ---------- --------------- ----------------
a          t1         a          t1                  0             646              675
a          t2         a          t2                  0             423              200
a                     a          小计                1            1069              875
b          x1         b          x1                  0             223              504
b          x2         b          x2                  0             283              484
b                     b          小计                1             506              988
c          y1         c          y1                  0             103              333
c          y2         c          y2                  0            1842             1285
c                     c          小计                1            1945             1618
d          s1         d          s1                  0             204              606
d                     d          小计                1             204              606
                      总计       总计                3            3724             4087
 
12 rows selected

对于全角和半角互换，oracle 提供了两个函数to_multi_byte和to_single_byte函数

 select to_multi_byte('1234') from dual;
 
TO_MULTI_BYTE('1234')
---------------------
１２３４
 select to_single_byte('１２３４') from dual;
 
TO_SINGLE_BYTE('１２３４')
--------------------------
1234

--create directory 
create directory ULTLOBDIR as 'd:'

--create table
create table blobtest(col1 BLOB);
create table clobtest(col1 cLOB);

--insert BLOB
declare
a_blob BLOB;
bfile_name BFILE := BFILENAME('ULTLOBDIR','teslob.doc');
begin
insert into blobtest values (empty_blob())
returning col1 into a_blob;
dbms_lob.fileopen(bfile_name);
dbms_lob.loadfromfile(a_blob, bfile_name, dbms_lob.getlength(bfile_name));
dbms_lob.fileclose(bfile_name);
commit;
end;

--update BLOB
declare
a_blob BLOB;
bfile_name BFILE := BFILENAME('ULTLOBDIR','log.txt');
begin
update blobtest set col1=empty_blob() where rownum=1
returning col1 into a_blob;
dbms_lob.fileopen(bfile_name);
dbms_lob.loadfromfile(a_blob, bfile_name, dbms_lob.getlength(bfile_name));
dbms_lob.fileclose(bfile_name);
commit;
end;

--insert CLOB
declare
a_clob CLOB;
bfile_name BFILE := BFILENAME('ULTLOBDIR','teslob.doc');
begin
insert into clobtest values (empty_clob())
returning col1 into a_clob;
dbms_lob.fileopen(bfile_name);
dbms_lob.loadfromfile(a_clob, bfile_name, dbms_lob.getlength(bfile_name));
dbms_lob.fileclose(bfile_name);
commit;
end;

--update CLOB
declare
a_clob CLOB;
bfile_name BFILE := BFILENAME('ULTLOBDIR','log.txt');
begin
update clobtest set col1=empty_clob() where rownum=1
returning col1 into a_clob;
dbms_lob.fileopen(bfile_name);
dbms_lob.loadfromfile(a_clob, bfile_name, dbms_lob.getlength(bfile_name));
dbms_lob.fileclose(bfile_name);
commit;
end;

--查询是否成功
select dbms_lob.getlength(col1) from blobtest;
select dbms_lob.getlength(col1) from clobtest;

1、procedure

CREATE [ OR REPLACE] PROCEDURE [schema.]procedure_name
[parameter_lister]
{AS|IS}
declaration_section
BEGIN
executable_section
[EXCEPTION
exception_section]
END [procedure_name]
--举例
create or replace
procedure dos_fx
is
cursor c1 is 
select get from dos_gj;              
begin
 for c2 in c1 loop
 insert into dos_gj_1(ip,gettime,get)values(REGEXP_SUBSTR( c2.get, '(\d{1,2}|1\d\d|2[0-4]\d|25[0-5])(\.(\d{1,2}|1\d\d|2[0-4]\d|25[0-5])){3} '),
 REGEXP_SUBSTR( c2.get, '^(\d{4})-(\d{2})-(\d{2}) (\d{2}:\d{2}:\d{2})'),c2.get);
 end loop;
 commit;
end;

2、function

CREATE [ OR REPLACE] FINCTION [schema.]function_name
[parameter_list]
RETURN returning_datatype
{AS|IS}
declaration_section
BEGIN
executable_section
[EXCEPTION]
exception_section
END [procedure_name]
--举例
CREATE OR REPLACE function fn_md5(input_string VARCHAR2) return varchar2
IS
raw_input RAW(128) := UTL_RAW.CAST_TO_RAW(input_string);
decrypted_raw RAW(2048);
error_in_input_buffer_length EXCEPTION;
BEGIN
sys.dbms_obfuscation_toolkit.MD5(input => raw_input,checksum => decrypted_raw);
return rawtohex(decrypted_raw);
END;

3、package

--header
CREATE [OR REPLACE] PACKAGE package_name
{AS|IS}
public_variable_declarations |
public_type_declarations |
public_exception_declarations |
public_cursor_declarations |
function_declarations |
procedure_specifications
END [package_name]
--body
CREATE [OR REPLACE] PACKAGE BODY package_name
{AS|IS}
private_variable_declarations |
private_type_declarations |
private_exception_declarations |
private_cursor_declarations |
function_declarations |
procedure_specifications
END [package_name]
--举例
--header
create or replace
package pk_t1
as
procedure get_num(getnum in number,aname varchar2);
end pk_t1;
--body
create or replace
package body pk_t1
as
procedure get_num(getnum in number,aname varchar2)
is 
begin
 insert into shell_1 values(getnum,aname);
end;
end pk_t1;

4、trigger

CREATE [OR REPLACE] TRIGGER trigger_name
{before|after|instead of} event
ON {table_or_view_name|DATABASE}
[FOR EACH ROW[WHEN condition]]
trigger_body
--举例
create or replace trigger add_shell
before update 
on shell_1 for each row
declare
begin
 if :OLD.name!=:new.name then
  :new.name:='ggggg';
 end if;
end;