（转）DB2常用SQL的写法
DB2常用SQL的写法(持续更新中...)-- Author: lavasoft
-- Date:2006-12-14
-- 创建一个自定义单值类型
createdistinct type var_newtype
as decimal(5,2) with comparisons;
-- var_newtype 类型名
-- decimal(5,2) 实际的类型
-- 删除一个自定义单值类型
drop distinct type var_newtype;
-- 创建一个自定义结构数据类型
create type my_type as(
username varchar(20),
department integer,
salary decimal(10,2))
not final
mode db2sql;
-- 修改自定义结构数据类型,我目前还没有发现删除属性的方法.
alter type my_type
add attribute hiredate date;
-- 删除自定义结构数据类型
drop type my_type;
-- 获取系统当前日期
select current date from sysibm.sysdummy1;
select current time from sysibm.sysdummy1;
select current timestamp from sysibm.sysdummy1;
--sysibm.sysdummy1表是一个特殊的内存中的表，用它可以发现如上面演示的 DB2 寄存器的值。您也可以使用关键字 VALUES 来对寄存器或表达式求值。
VALUES current date;
VALUES current time;
VALUES current timestamp;
-- VALUES的更多用法
VALUES 2+5;
VALUES 'hello lavasoft!';
values 56
union all
values 45;
values 1,2,3,4,5,6
union all
values 7,8,9,10,11,12
order by 1;
-- 更多变态级DB2 SQL写法,AnyOneTable表示任意一个存在的表
select 234 from AnyOneTable;
select distinct 234 from AnyOneTable;
select distinct 234 as 1 from AnyOneTable;
select 'DB2变态级的SQL哈哈' from AnyOneTable;
select distinct 'DB2变态级的SQL哈哈' from AnyOneTable;
select distinct 'DB2变态级的SQL哈哈' as 1 from AnyOneTable;
--(嘿嘿,好玩吧,你可以用任意一个表来当sysibm.sysdummy1用.不过不推荐这么做,除非你不记得sysibm.sysdummy1怎么写了,Oracle中(对应dual)也一样!哈哈哈哈!)
-- 定义变量,还可以设定默认值,给变量赋值
declare var1 char(2);
declare var2 int default 0;
set var1 = 'aa';
set var2 =23;
--创建一个动态游标变量
declare d_cur integer;
-- 给变量赋值的另一种方法
values expr1, expr2, expr3 into a, b, c;
-- 相当于
set a = expr1;
set b = expr2;
set c = expr3;
-- 还有一种赋值方式
set prodname = (case
when (name is not null) then name
when (namestr is not null) then namestr
elsedefaultname
end);
-- 相当于
set prodname = coalesce(name, namestr, defaultname);
--这个类似oracle的decode()和nvl()函数的合并.
-- 定义一个游标
declare cur1 cursor with return to client for select * from dm_hy;
declare cur2 cursor for select * from dm_hy; -- 静态游标
-- 创建数据表,并添加注释,插入数据.
CREATE TABLE tbr_catalog (
id bigintnot nullgenerated by default as identity,
type smallint not null,
name varchar(255),
parentid bigint,
cataloglevel bigint,
description varchar(255),
PRIMARY KEY(id)
);
comment on table tbr_catalog is 'Birt报表目录表';
comment on column tbr_catalog.ID is '标识';
comment on column tbr_catalog.type is '目录类型';
comment on column tbr_catalog.name is '目录名称';
comment on column tbr_catalog.parentid is '目录父标识';
comment on column tbr_catalog.cataloglevel is '目录层次';
comment on column tbr_catalog.description is '目录描述';
-- 给数据表插入数据
insert into tbr_catalog(id, type, name, parentid, cataloglevel, description)
values (1, 0, '系统报表', 0, 0, '');
insert into tbr_catalog(id, type, name, parentid, cataloglevel, description)
values (2, 1, '用户报表', 0, 0, '');
-- 创建外键
alter table tbr_storage
add constraint fk_tbr_storage
foreign key (catalogid)
references tbr_catalog(id);
-- 更改表,添加列
alter table aaa add sex varchar(1);
-- 更改表,删除列
alter table aaa drop column sex;
-- 去掉参数前后的空格
rtrim(dm_hy.mc);
-- 定义临时表,通过已有person表来创建
declare global temporary table gbl_temp
like person
on commit delete rows --提交时删除数据
not logged -- 不在日志中纪录
in usr_tbsp -- 选用表空间
-- 此语句创建一个名为 gbl_temp 的用户临时表。定义此用户临时表 所使用的列的名称和说明与 person 的列的名称和说明完全相同。
-- 创建有两个字段的临时表
-- 定义一个全局临时表tmp_hy
declare global temporary table session.tmp_hy
(
dm varchar(10),
mc varchar(10)
)
with replace -- 如果存在此临时表，则替换
not logged;-- 不在日志里纪录
-- 给临时表插入三条数据
insert into session.tmp_hy values('1','1');
insert into session.tmp_hy values('1','1');
insert into session.tmp_hy values('1','1');
-- 通过查询批量插入数据
inster into tab_bk(select code,name from table book);
-- select ... into的用法
select * into :h1, :h2, :h3, :h4
from emp
where empno = '528671';
-- 语句的流程控制
if() then
open cur1
fetch cur1 into t_equipid;
while(at_end<>1)do
......
set t_temp=0;
end while;
close cur1;
else
......
end if;
-- 外连接
select empno,deptname,projname
from (emplyoee
left outer join project
on respemp=empon)
left outer join department
on mgrno=empno;
-- in、like、order by(... ASC|DESC)的用法
select * from book t
where t.name like '%J_编程%'
and t.code in（'J565333','J565222');
order by t.name asc
-- 汇总表(概念复杂，难以理解，不常用）
create summary table sumy_stable1
as (select workdept,
count(*) as reccount,
sum(salary) as salary,
sum(bonus) as bonus
from employee group by workdept)
data initially deferred
refresh immediate;
-- 使用SQL一次处理一个集合语义
-- （优化前） select语句中每行的过程层和数据流层之间都有一个上下文切换
declare cur1 cursor for col1,col2 from tab_comp;
open cur1;
fetch cur1 into v1,v2;
while SQLCODE<> 100 do
if (v1>20) then
insert into tab_sel values(20,v1);
else
insert into tab_sel values(v1,v2);
end if;
fetch cur1 into v1,v2;
end while;
-- （优化后）没有过程层和数据流层之间的上下文切换
declare cur1 cursor for col1,col2 from tab_comp;
open cur1;
fetch cur1 into v1,v2;
while SQLCODE<> 100 do
insert into tab_sel(select (case
when col1>20 then 20
else col1
end),
col2
from tab_comp);
fetch cur1 into v1,v2;
end while;
-- DB2函数分三类：列函数、标量函数、表函数
-- 列函数输入一组数据，输出单一结果。
-- 标量函数接收一个值，返回另外一个值。
-- 表函数只能用于SQL语句的from字句中，它返回一个表的列，类似于一个已创建的常规表。
-- 下面是个标量函数的例子。
create function (salary int,bonus_percent int)
returns int
language SQL contains SQL
return(
salary * bonus_percent/100
)
-- 下面是表函数
create function get_marks(begin_range int,end_range int)
returns table(cid candidate_id,
number test_id,
score score)
language SQL reads SQL DATA
return
select cid,number,score
from test_taken
where salary between (begin_range) and score(end_range)
example 1: define a scalar function that returns the tangent of a value using the existing sine and cosine functions.
create function tan (x double)
returns double
language sql
contains sql
no external action
deterministic
return sin(x)/cos(x)
example 2: define a transform function for the structured type person.
create function fromperson (p person)
returns row (name varchar(10), firstname varchar(10))
language sql
contains sql
no external action
deterministic
return values (p..name, p..firstname)
example 3: define a table function that returns the employees in a specified department number.
create function deptemployees (deptno char(3))
returns table (empno char(6),
lastname varchar(15),
firstname varchar(12))
language sql
reads sql data
no external action
deterministic
return
select empno, lastname, firstnme
from employee
where employee.workdept = deptemployees.deptno
example 4: define a scalar function that reverses a string.
create function reverse(instr varchar(4000))
returns varchar(4000)
deterministic no external action contains sql
begin atomic
declare revstr, reststr varchar(4000) default '';
declare len int;
if instr is null then
return null;
end if;
set (reststr, len) = (instr, length(instr));
while len > 0 do
set (revstr, reststr, len)
= (substr(reststr, 1, 1) concat revstr,
substr(reststr, 2, len - 1),
len - 1);
end while;
return revstr;
end
example 4: define the table function from example 4 with auditing.
create function deptemployees (deptno char(3))
returns table (empno char(6),
lastname varchar(15),
firstname varchar(12))
language sql
modifies sql data
no external action
deterministic
begin atomic
insert into audit
values (user,
'table: employee prd: deptno = ' concat deptno);
return
select empno, lastname, firstnme
from employee
where employee.workdept = deptemployees.deptno
end
-- for循环语句的用法
begin atomic
declare fullname char(40);
for vl as
select firstnme, midinit, lastname from employee
do
set fullname = lastname concat ','
concat firstnme concat ' ' concat midinit;
insert into tnames values (fullname);
end for
end
-- leave的用法
create procedure leave_loop(out counter integer)
language sql
begin
declare v_counter integer;
declare v_firstnme varchar(12);
declare v_midinit char(1);
declare v_lastname varchar(15);
declare at_end smallint default 0;
declare not_found condition for sqlstate '02000';
declare c1 cursor for
select firstnme, midinit, lastname
from employee;
declare continue handler for not_found
set at_end = 1;
set v_counter = 0;
open c1;
fetch_loop:
loop
fetch c1 into v_firstnme, v_midinit, v_lastname;
if at_end <> 0 then leave fetch_loop;
end if;
set v_counter = v_counter + 1;
end loop fetch_loop;
set counter = v_counter;
close c1;
end
-- if语句的用法
create procedure update_salary_if
(in employee_number char(6), inout rating smallint)
language sql
begin
declare not_found condition for sqlstate '02000';
declare exit handler for not_found
set rating = -1;
if rating = 1
then update employee
set salary = salary * 1.10, bonus = 1000
where empno = employee_number;
elseif rating = 2
then update employee
set salary = salary * 1.05, bonus = 500
where empno = employee_number;
else update employee
set salary = salary * 1.03, bonus = 0
where empno = employee_number;
end if;
end
-- loop的用法
create procedure loop_until_space(out counter integer)
language sql
begin
declare v_counter integer default 0;
declare v_firstnme varchar(12);
declare v_midinit char(1);
declare v_lastname varchar(15);
declare c1 cursor for
select firstnme, midinit, lastname
from employee;
declare continue handler for not found
set counter = -1;
open c1;
fetch_loop:
loop
fetch c1 into v_firstnme, v_midinit, v_lastname;
if v_midinit = ' ' then
leave fetch_loop;
end if;
set v_counter = v_counter + 1;
end loop fetch_loop;
set counter = v_counter;
close c1;
end
-- return的用法
begin
...
goto fail
...
success: return 0
fail: return -200
end
-- set变量 的用法
set new_var.salary = 10000, new_var.comm = new_var.salary;
or:
set (new_var.salary, new_var.comm) = (10000, new_var.salary);
set (new_var.salary, new_var.comm)
= (select avg(salary), avg(comm)
from employee e
where e.workdept = new_var.workdept);
-- whenever的用法
exec sql whenever sqlerror goto handlerr;
exec sql whenever sqlwarning continue;
exec sql whenever not found go to enddata;
-- while的用法
create procedure dept_median
(in deptnumber smallint, out mediansalary double)
language sql
begin
declare v_numrecords integer default 1;
declare v_counter integer default 0;
declare c1 cursor for
select cast(salary as double)
from staff
where dept = deptnumber
order by salary;
declare exit handler for not found
set mediansalary = 6666;
set mediansalary = 0;
select count(*) into v_numrecords
from staff
where dept = deptnumber;
open c1;
while v_counter < (v_numrecords / 2 + 1) do
fetch c1 into mediansalary;
set v_counter = v_counter + 1;
end while;
close c1;
end
-- set schema的用法
set schema rick
-- DB2保留关键字
add deterministicleave restart
after disallow left restrict
alias disconnect like result
all distinct linktype result_set_locator
allocate do local return
allow double locale returns
alter drop locator revoke
and dsnhattr locators right
any dssize lock rollback
application dynamic lockmax routine
as each locksize row
associate editproc long rows
asutime else loop rrn
audit elseif maxvalue run
authorization encoding microsecond savepoint
aux end microsecondsschema
auxiliary end-exec minute scratchpad
before end-exec1 minutes second
begin erase minvalue seconds
between escape mode secqty
binary except modifies security
bufferpool exception month select
by excluding months sensitive
cache execute new set
call exists new_table signal
called exit no simple
capture external nocache some
cardinality fenced nocycle source
cascaded fetch nodename specific
case fieldproc nodenumber sql
cast file nomaxvalue sqlid
ccsid final nominvalue standard
char for noorder start
character foreign not static
check free null stay
close from nulls stogroup
cluster full numparts stores
collection function obid style
collid general of subpages
column generated old substring
comment get old_table synonym
commit global on sysfun
concat go open sysibm
condition goto optimizationsysproc
connect grant optimize system
connection graphic option table
constraint group or tablespace
contains handler order then
continue having out to
count hold outer transaction
count_big hour overriding trigger
create hours package trim
cross identity parameter type
current if part undo
current_date immediate partition union
current_lc_ctype in path unique
current_path including piecesize until
current_server increment plan update
current_time index position usage
current_timestampindicator precision user
current_timezone inherit prepare using
current_user inner primary validproc
cursor inout priqty values
cycle insensitive privileges variable
data insert procedure variant
database integrity program vcat
day into psid view
days is queryno volumes
db2general isobid read when
db2genrl isolation reads where
db2sql iterate recovery while
dbinfo jar references with
declare java referencing wlm
default join release write
defaults key rename year
definition label repeat years
delete language reset
descriptor lc_ctype resignal
-- SQL99关键字
absolute describe module session
action destroy names session_user
admin destructor national sets
aggregate diagnostics natural size
are dictionary nchar smallint
array domain nclob space
asc equals next specifictype
assertion every none sqlexception
at exec numeric sqlstate
bit false object sqlwarning
blob first off state
boolean float only statement
both found operation structure
breadth grouping ordinalitysystem_user
cascade host output temporary
catalog ignore pad terminate
class initialize parametersthan
clob initially partial time
collate input postfix timestamp
collation int prefix timezone_hour
completion integer preorder timezone_minute
constraints intersect preserve trailing
constructor interval prior translation
correspondinglarge public treat
cube last real true
current_role lateral recursive under
date leading ref unknown
deallocate less relative unnest
dec level role value
decimal limit rollup varchar
deferrable localtime scope varying
deferred localtimestampscroll whenever
depth map search without
deref match section work
desc modify sequence zone
--create type (结构化的)用法
create type dept as
(dept name varchar(20),
max_emps int)
ref using int
mode db2sql
create type emp as
(name varchar(32),
serialnum int,
dept ref(dept),
salary decimal(10,2))
mode db2sql
create type mgr under emp as
(bonus decimal(10,2))
mode db2sql
create type address_t as
(street varchar(30),
number char(15),
city varchar(30),
state varchar(10))
not final
mode db2sql
method samezip (addr address_t)
returns integer
language sql
deterministic
contains sql
no external action,
method distance (address_t)
returns float
language c
deterministic
parameter style sql
no sql
no external action
create type germany_addr_t under address_t as
(family_name varchar(30))
not final
mode db2sql
create type us_addr_t under address_t as
(zip varchar(10))
not final
mode db2sql
create type project as
(proj_namevarchar(20),
proj_id integer,
proj_mgr mgr,
proj_leademp,
location addr_t,
avail_date date)
mode db2sql
-- create type mapping的用法
create type mapping my_oracle_date
from local type sysibm.date
to server type oracle
remote type date
create type mapping my_oracle_dec
from local type sysibm.decimal(10,2)
to server oracle1
remote type number(,2)
create type mapping my_oracle_char
from local type sysibm.varchar()
to server oracle1
remote type char()
create type mapping my_oracle_dec
to local type sysibm.decimal(10,2)
from server oracle2
remote type number(10,2)
-- create user mapping的用法
create user mapping for rspalten
server server390
options
(remote_authid 'system',
remote_password 'manager')
create user mapping for marcr
server oracle1
options
(remote_password 'nzxczy')
-- case的用法
case v_workdept
when'a00'
then update department
set deptname = 'data access 1';
when 'b01'
then update department
set deptname = 'data access 2';
else update department
set deptname = 'data access 3';
end case
case
when v_workdept = 'a00'
then update department
set deptname = 'data access 1';
when v_workdept = 'b01'
then update department
set deptname = 'data access 2';
else update department
set deptname = 'data access 3';
end case
-- create trigger的用法
create trigger new_hired
after insert on employee
for each row
update company_stats set nbemp = nbemp + 1
create trigger former_emp
after delete on employee
for each row
update company_stats set nbemp = nbemp - 1
create trigger reorder
after update of on_hand, max_stocked on parts
referencing new as n
for each row
when (n.on_hand < 0.10 * n.max_stocked)
begin atomic
values(issue_ship_request(n.max_stocked - n.on_hand, n.partno));
end
create trigger raise_limit
after update of salary on employee
referencing new as n old as o
for each row
when (n.salary > 1.1 * o.salary)
signal sqlstate '75000' set message_text='salary increase>10%'
create trigger stock_status
no cascade before update of quote on currentquote
referencing new as newquote old as oldquote
for each row
begin atomic
set newquote.status =
case
when newquote.quote >
(select max(quote) from quotehistory
where symbol = newquote.symbol
and year(quote_timestamp) = year(current date) )
then 'high'
when newquote.quote < (select min(quote) from quotehistory
where symbol = newquote.symbol
and year(quote_timestamp) = year(current date) )
then 'low'
when newquote.quote > oldquote.quote
then 'rising'
when newquote.quote < oldquote.quote
then 'dropping'
when newquote.quote = oldquote.quote
then 'steady'
end;
end
create trigger record_history
after update of quote on currentquote
referencing new as newquote
for each row
begin atomic
insert into quotehistory
values (newquote.symbol, newquote.quote, current timestamp);
end
-- create tablespace 的用法
create tablespace payroll
managed by database
using (device'/dev/rhdisk6' 10000,
device '/dev/rhdisk7' 10000,
device '/dev/rhdisk8' 10000)
overhead 12.67
transferrate 0.18
create tablespace accounting
managed by system
using ('d:\acc_tbsp', 'e:\acc_tbsp', 'f:\acc_tbsp')
extentsize 64
prefetchsize 32
create tablespace plans
managed by database
using (device '/dev/rhdisk0' 10000, device '/dev/rn1hd01' 40000)
on dbpartitionnum (1)
using (device '/dev/rhdisk0' 10000, device '/dev/rn3hd03' 40000)
on dbpartitionnum (3)
using (device '/dev/rhdisk0' 10000, device '/dev/rn5hd05' 40000)
on dbpartitionnum (5)
-- 带case查询条件语句
select (case b.organtypecode
when 'D' then
b.parent
when 'S' then
b.parent
else
b.id
end),
b.name
from A_ORGAN b
where b.id = 999
重新安装DB2后 创建数据库提示数据库别名已经存在的问题
这个原因，是由于在卸载DB2之后，由于没有在本地文件系统中将安装的文件清理干净，所以倒是了在DB2的本地目录中还存在这卸载的时候DB2中创建的数据库的别名(由于在系统目录中已经不存在这些别名了，所以在控制中心的视图中是看不见的)；具体的处理方法是：
1.把本地的目录信息重新设置到系统目录中去：
catalog db sample on d:
2.drop掉这个database
drop db sample
3.重新创建这个database
create db sample
注1： 如果不做第一步，直接做第二步系统会提示找不到sample的数据库别名，因为此时系统的目录中没有sample这样的数据库别名，所以我们必须把本地目录的数据库别名信息同步到系统目录中，然后在去做第二步才能真正的drop这个数据库。
注2：查看目录信息的命令是：
list db directory ----查看系统的目录信息
list db directory on d: -----查看制定的本地路径的目录信息
在重新catalog之前最好使用这两个命令查看一下具体的目录信息
页:
[1]