查询列行转换

MS SQL Server:--------------------------------------
列转化成行
--> --> (Roy)生成測試數據

if not object_id('Class') is null
    drop table Class
Go
Create table Class([Student] nvarchar(2),[Course] nvarchar(2),[Score] int)
Insert Class
select N'张三',N'语文',78 union all
select N'张三',N'数学',87 union all
select N'张三',N'英语',82 union all
select N'张三',N'物理',90 union all
select N'李四',N'语文',65 union all
select N'李四',N'数学',77 union all
select N'李四',N'英语',65 union all
select N'李四',N'物理',85
Go

动态:

declare @s nvarchar(4000)
set @s=''
Select     @s=@s+','+quotename([Course])+'=max(case when [Course]='+quotename([Course],'''')+' then [Score] else 0 end)'
from Class group by[Course]
exec('select [Student]'+@s+' from Class group by [Student]')


生成静态:

select
    [Student],
    [数学]=max(case when [Course]='数学' then [Score] else 0 end),
    [物理]=max(case when [Course]='物理' then [Score] else 0 end),
    [英语]=max(case when [Course]='英语' then [Score] else 0 end),
    [语文]=max(case when [Course]='语文' then [Score] else 0 end)
from
    Class
group by [Student]

GO

/*
Student 数学          物理          英语          语文
------- ----------- ----------- ----------- -----------
李四      77          85          65          65
张三      87          90          82          78

(2 行受影响)
*/



行转化成列
if not object_id('Class') is null
    drop table Class
Go
Create table Class([Student] nvarchar(2),[数学] int,[物理] int,[英语] int,[语文] int)
Insert Class
select N'李四',77,85,65,65 union all
select N'张三',87,90,82,78
Go



动态:

declare @s nvarchar(4000)
select @s=isnull(@s+' union all ','')+'select [Student],[Course]='+quotename(Name,'''')--isnull(@s+' union all ','') 去掉字符串@s中第一个union all
+',[Score]='+quotename(Name)+' from Class'
from syscolumns where ID=object_id('Class') and Name not in('Student')--排除不转换的列
order by Colid
exec('select * from ('+@s+')t order by [Student],[Course]')--增加一个排序

生成静态:
select *
from (select [Student],[Course]='数学',[Score]=[数学] from Class union all
select [Student],[Course]='物理',[Score]=[物理] from Class union all
select [Student],[Course]='英语',[Score]=[英语] from Class union all
select [Student],[Course]='语文',[Score]=[语文] from Class)t
order by [Student],[Course]

go

/*
Student Course Score
------- ------- -----------
李四      数学      77
李四      物理      85
李四      英语      65
李四      语文      65
张三      数学      87
张三      物理      90
张三      英语      82
张三      语文      78

(8 行受影响)
*/


Oracle:-----------------------------
oracle列转行2009年07月24日 星期五 15:02student subject grade
---------------------------
student1 语文 80
student1 数学 70
student1 英语 60
student2 语文 90
student2 数学 80
student2 英语 100
……
转换为
语文 数学 英语
student1 80 70 60
student2 90 80 100
……
语句如下：
select student,sum(decode(subject,'语文', grade,null)) "语文",
sum(decode(subject,'数学', grade,null)) "数学",
sum(decode(subject,'英语', grade,null)) "英语"
from table
group by student

2、不定列行列转换
如
c1 c2
--------------
1 我
1 是
1 谁
2 知
2 道
3 不
……
转换为
1 我是谁
2 知道
3 不
这一类型的转换必须借助于PL/SQL来完成，这里给一个例子
CREATE OR REPLACE FUNCTION get_c2(tmp_c1 NUMBER)
RETURN VARCHAR2
IS
Col_c2 VARCHAR2(4000);
BEGIN
FOR cur IN (SELECT c2 FROM t WHERE c1=tmp_c1) LOOP
Col_c2 := Col_c2||cur.c2;
END LOOP;
Col_c2 := rtrim(Col_c2,1);
RETURN Col_c2;
END;
/
SQL> select distinct c1 ,get_c2(c1) cc2 from table;即可
大量数据行列转换
机型统计
create table temp_devices as
select trunc(t.oper_time) time,
substr(t.device_name,1,instr(t.device_name,'(')-1) as dev,
count(t.num) as numcount
from view_mobil_from_user t
where trunc(t.oper_time)>= to_date('20041201','yyyymmdd') and
trunc(t.oper_time)<= to_date('20041228','yyyymmdd') and
t.fld_area_id = 5
group by trunc(t.oper_time),substr(t.device_name,1,instr(t.device_name,'(')-1)



select t.dev 设备名称,
t1.numcount 日期1,
t2.numcount 日期2,
t3.numcount 日期3,
t4.numcount 日期4,
t5.numcount 日期5,
t6.numcount 日期6,
t7.numcount 日期7,
t8.numcount 日期8,
t9.numcount 日期9,
t10.numcount 日期10,
t11.numcount 日期11,
t12.numcount 日期12,
t13.numcount 日期13,
t14.numcount 日期14,
t15.numcount 日期15,
t16.numcount 日期16,
t17.numcount 日期17,
t18.numcount 日期18,
t19.numcount 日期19,
t20.numcount 日期20,
t21.numcount 日期21,
t22.numcount 日期22,
t23.numcount 日期23,
t24.numcount 日期24,
t25.numcount 日期25,
t26.numcount 日期26,
t27.numcount 日期27,
t28.numcount 日期28
from
(select distinct(dev) dev from temp_devices ) t,
(select * from temp_devices t where t.time = to_date('20041201','yyyymmdd')) t1,
(select * from temp_devices t where t.time = to_date('20041202','yyyymmdd')) t2,
(select * from temp_devices t where t.time = to_date('20041203','yyyymmdd')) t3,
(select * from temp_devices t where t.time = to_date('20041204','yyyymmdd')) t4,
(select * from temp_devices t where t.time = to_date('20041205','yyyymmdd')) t5,
(select * from temp_devices t where t.time = to_date('20041206','yyyymmdd')) t6,
(select * from temp_devices t where t.time = to_date('20041207','yyyymmdd')) t7,
(select * from temp_devices t where t.time = to_date('20041208','yyyymmdd')) t8,
(select * from temp_devices t where t.time = to_date('20041209','yyyymmdd')) t9,
(select * from temp_devices t where t.time = to_date('20041210','yyyymmdd')) t10,
(select * from temp_devices t where t.time = to_date('20041211','yyyymmdd')) t11,
(select * from temp_devices t where t.time = to_date('20041212','yyyymmdd')) t12,
(select * from temp_devices t where t.time = to_date('20041213','yyyymmdd')) t13,
(select * from temp_devices t where t.time = to_date('20041214','yyyymmdd')) t14,
(select * from temp_devices t where t.time = to_date('20041215','yyyymmdd')) t15,
(select * from temp_devices t where t.time = to_date('20041216','yyyymmdd')) t16,
(select * from temp_devices t where t.time = to_date('20041217','yyyymmdd')) t17,
(select * from temp_devices t where t.time = to_date('20041218','yyyymmdd')) t18,
(select * from temp_devices t where t.time = to_date('20041219','yyyymmdd')) t19,
(select * from temp_devices t where t.time = to_date('20041220','yyyymmdd')) t20,
(select * from temp_devices t where t.time = to_date('20041221','yyyymmdd')) t21,
(select * from temp_devices t where t.time = to_date('20041222','yyyymmdd')) t22,
(select * from temp_devices t where t.time = to_date('20041223','yyyymmdd')) t23,
(select * from temp_devices t where t.time = to_date('20041224','yyyymmdd')) t24,
(select * from temp_devices t where t.time = to_date('20041225','yyyymmdd')) t25,
(select * from temp_devices t where t.time = to_date('20041226','yyyymmdd')) t26,
(select * from temp_devices t where t.time = to_date('20041227','yyyymmdd')) t27,
(select * from temp_devices t where t.time = to_date('20041228','yyyymmdd')) t28
where t.dev=t1.dev(+) and
t.dev=t2.dev(+) and
t.dev=t3.dev(+) and
t.dev=t4.dev(+) and
t.dev=t5.dev(+) and
t.dev=t6.dev(+) and
t.dev=t7.dev(+) and
t.dev=t8.dev(+) and
t.dev=t9.dev(+) and
t.dev=t10.dev(+) and
t.dev=t11.dev(+) and
t.dev=t12.dev(+) and
t.dev=t13.dev(+) and
t.dev=t14.dev(+) and
t.dev=t15.dev(+) and
t.dev=t16.dev(+) and
t.dev=t17.dev(+) and
t.dev=t18.dev(+) and
t.dev=t19.dev(+) and
t.dev=t20.dev(+) and
t.dev=t21.dev(+) and
t.dev=t22.dev(+) and
t.dev=t23.dev(+) and
t.dev=t24.dev(+) and
t.dev=t25.dev(+) and
t.dev=t26.dev(+) and
t.dev=t27.dev(+) and
t.dev=t28.dev(+)




1、默认值
2、截取字段 cun_col
3、需截取的表 cut_table
4、关键字
5、生成表最大列数
6、基础表选择条件A自动增加 条件S_where 自增标量名称S_increase 开始值 S_begin，结束值 S_end，步长 S_step
B特定结果集
7、生成结果存储表名




1、生成表
2、生成连接条件
3、生成列

create or replace procedure sp_tab_change(cut_table in varchar2,--需要截取的表
cut_col in varchar2,--用来截取的分类字段
cut_col_z in varchar2,--截取字段
cut_col_na in varchar2,--分类字段别名
col_name in varchar2,--列字段别名
def_value in varchar2,--默认值
S_where in varchar2,--子表在截取表中选择数据的条件
S_increase in varchar2,--自增变量名
S_begin in varchar2,--开始数字
S_end in varchar2,--结束数值
--S_step in varchar2,--步长
v_str out varchar2) --生成的语句
as --这个存储过程生成的sql语句还有点问题，需要删除最后的and

v_sql_t varchar2(10000);
v_tmp_tab varchar2(5000);
v_tmp_whe varchar2(5000);
v_tmp_wher varchar2(5000);
v_tmp_col varchar2(5000);
c_tmp_col number(10);
c_tmp number(10);



begin
c_tmp :=S_begin;
v_tmp_tab :=' ';
v_tmp_col :=' ';
v_tmp_whe :=' ';
v_tmp_wher:=' ';
for v_temp in S_begin..S_end loop
v_tmp_whe :=replace(S_where,S_increase,c_tmp);
v_tmp_tab := v_tmp_tab||' (select * from '||cut_table||' where '||v_tmp_whe||') t'||c_tmp||',';
v_tmp_col:= v_tmp_col||',nvl(t'||c_tmp||'.'||cut_col_z||','||def_value||') '||col_name||c_tmp;
v_tmp_wher:= v_tmp_wher||' t.'||cut_col||'=t'||c_tmp||'.'||cut_col||'(+) and';
c_tmp := c_tmp+1;
end loop;
v_sql_t := ' select t.'||cut_col||' '||cut_col_na||v_tmp_col||' '||
' from '||v_tmp_tab||'(select distinct('||cut_col||') '||cut_col||' from '||cut_table||') t '||
' where '||v_tmp_wher;
v_str:=v_sql_t;
end sp_tab_change;



-- Create table
create table TEMP_DEVICES
(
TIME DATE,
DEV VARCHAR2(60),
NUMCOUNT NUMBER
)
tablespace ETS_USER
pctfree 10
pctused 40
initrans 1
maxtrans 255
storage
(
initial 1M
next 1M
minextents 1
maxextents unlimited
pctincrease 0
);