Oracle_查询字段(字符串拼接)

*Oracle_查询字段(字符串拼接)*

1 连接符号“||”的使用，能将多个表中不同的字段进行拼接。

1）单表的两个字段拼接

select  bxze||'#'||jkdh frombx_bxdj

结果：55471#BX1200025

2）多表联合查询，表间字段的拼接，bmmc为gg_bmxx中的字段，jkdh为bx_bxdj表的字段

select  bmmc||'#'||jkdh frombx_bxdj,gg_bmxx where bx_bxdj.bmxh=gg_bmxx.id

结果：工程造价中心#BX1200274

2 树形结构结果查询方法

参考原文 http://blog.csdn.net/precipitant/article/details/1427566

SQL>   select  no,q   from   test  

      2    /  

   

  NO                  Q 

  ----------  ------------------------------  

  001                n1 

  001                n2 

  001                n3 

  001                n4 

  001                n5 

  002                m1 

  003                t1 

  003                t2 

  003                t3 

  003                t4 

  003                t5 

  003                t6   

  12   rows  selected  

  求得如下的结果：  

  001                n1;n2;n3;n4;n5 

  002                m1 

  003                t1;t2;t3;t4;t5;t6  

 

解题：对表数据进行分析，进行编号和分组编号，如下图中的rn，rn1

 


将上述的sql作为子查询，对a=001的数据进行拼接



进一步帅选

select t.*,

       (selectmax(sys_connect_by_path(b, ';')) result

          from(select a,

                       b,

                       rn,

                       lead(rn)over(partition by a order by rn) rn1

                  from(select a,

                               b,

                               row_number()over(order by a, b desc) rn

                          fromlucheng))

         startwith a = t.a

                andrn1 is null

        connectby rn1 = prior rn) value

  from (select distinct afrom lucheng) t

--------------------------------------------------------------------

A=select a,b,row_number() over(order by a, bdesc) rn from lucheng 最初的排序rn=1-12

---------------------------------------------------------------------

select a,

                       b,

                       rn,

                       lead(rn)over(partition by a order by rn) rn1

                  from(A) --新增一列r1

---------------------------------------------------------------------

结果

a        value

002      ;m1

001      ;n1;n2;n3;n4;n5

003      ;t1;t2;t3;t4;t5;t6

3 航程问题

a    b     c    d 

----------------------

999  x     y    1

999  y     z    2

999  z     m    3

999  m     l    4

求得999的航线是x-y-z-m-l.
select t1.b || '-' || t2.b

from (select a, b from A where d = 1) t1,

    (selecta, replace(wm_concat(c), ',', '-') b from A start with d = 1 connect by b =prior c group by a) t2

where t1.a =t2.a

简化格式：select x from(sql1)t1,(sql2)t2 where t1.a=t2.a

replace('x','y','z')函数表示将x字符串中的y符号同z符号代替

如若不使用替换函数

select a, wm_concat(c) b

          fromlucheng --where d<5

         startwith d = 1

        connectby b = prior c

         groupby a

结果  a  b--->999  y,z,m,l                 wm_concat函数默认用，号分隔

sql1的值为

a   b

999  x

--------------------

sql2的值为

a    b

999 y-z-m-l

4 WMSYS.WM_CONCAT 函数的用法
参考原文 http://blog.sina.com.cn/s/blog_5c4736800100l2qw.html
SQL> select * from idtable;--所有数据
 

        ID NAME
-----------------------------------------------

        10 ab

        10 bc

        10 cd

        20 hi

        20 ij

        20 mn
6 rowsselected
SQL> select id,wmsys.wm_concat(name) name from idtable group by id;

        ID NAME
------------------------------------------------------

        10 ab,bc,cd

        20 hi,ij,mn
SQL> select id,wmsys.wm_concat(name) over (order by id) namefrom
idtable;

        ID NAME
-------------------------------------------------------------------

        10 ab,bc,cd

        10 ab,bc,cd

        10 ab,bc,cd

        20 ab,bc,cd,hi,ij,mn

        20 ab,bc,cd,hi,ij,mn

        20 ab,bc,cd,hi,ij,mn
6 rowsselected
SQL> select id,wmsys.wm_concat(name) over (order by id,name) name from idtable;

        ID NAME
-------------------------------------------------------------------

        10 ab

        10 ab,bc

        10 ab,bc,cd

        20 ab,bc,cd,hi

        20 ab,bc,cd,hi,ij

        20 ab,bc,cd,hi,ij,mn
6 rowsselected
个人觉得这个用法比较有趣.
SQL> select id,wmsys.wm_concat(name) over (partition by id) name
from idtable;

        ID NAME
-------------------------------------------------------------

        10 ab,bc,cd

        10 ab,bc,cd

        10 ab,bc,cd

        20 hi,ij,mn

        20 hi,ij,mn

        20 hi,ij,mn
6 rowsselected ----------------------------------------------------------

 select id,

        fid,

        bmmc,

        jgbh,

        SYS_CONNECT_BY_PATH(to_char(sxh,'00'), '.') sort

   from gg_bmxx

  where --gg_bmxx.jgbh = '001'

  gg_bmxx.fid = '4028826b38a2e4fc0138a337e68e001c'

  start with fid is null

 connect by prior gg_bmxx.id = gg_bmxx.fid

  order by sort, sxh

-----------------------------------------------------------

select id,

        fid,

        bmmc,

        jgbh,

        SYS_CONNECT_BY_PATH(to_char(sxh,'00'), '.') sort

   from gg_bmxx

  where gg_bmxx.jgbh ='001'

  start with fid ='4028826b38a2e4fc0138a337e68e001f'

 connect by prior gg_bmxx.id =gg_bmxx.fid

  order by sort, sxh;

 

如若某个表中存有字段类似(x,y,z),现将（x,y,z）查询出来对应的内容（m,l,n）.

selectWMSYS.WM_CONCAT(g.dmmc) as lbstr

 fromgg_sjzd g

 wherelength(g.id)>4

 andinstr(

(select t.gslbfrom jc_czy t where t.id=?),g.id)>0

------------------x,y,z->m,l,n-----------适用于单个记录查询

SELECTWMSYS.WM_CONCAT(DLJGJG.DLJGMC) zjmc

  FROMJD_DLJGJG DLJGJG, JD_CGDLJG CGDLJG

 WHEREDLJGJG.DLJGBH = CGDLJG.ID

   ANDDLJGJG.CQGZBH = ?

----相同的标识下的信息拼接如：某班级的若干学生名称：张三，李四，王五（适用单个记录查询）---