通过分组更新SQL查询

Question

I'm dealing with some legacy data in an Oracle table and have the following

--------------------------------------------
| RefNo                         |     ID   |                          
--------------------------------------------
| FOO/BAR/BAZ/AAAAAAAAAA        |      1   |
| FOO/BAR/BAZ/BBBBBBBBBB        |      1   |
| FOO/BAR/BAZ/CCCCCCCCCC        |      1   |
| FOO/BAR/BAZ/DDDDDDDDDD        |      1   |
--------------------------------------------

For each of the /FOO/BAR/BAZ/% records I want to make the ID a Unique incrementing number. Is there a method to do this in SQL?

Thanks in advance

EDIT

Sorry for not being specific. I have several groups of records /FOO/BAR/BAZ/, /FOO/ZZZ/YYY/. The same transformation needs to occur for each of these other (example) groups. The recnum can't be used I want ID to start from 1, incrementing, for each group of records I have to change.

Sorry for making a mess of my first post. Output should be

--------------------------------------------
| RefNo                         |     ID   |                          
--------------------------------------------
| FOO/BAR/BAZ/AAAAAAAAAA        |      1   |
| FOO/BAR/BAZ/BBBBBBBBBB        |      2   |
| FOO/BAR/BAZ/CCCCCCCCCC        |      3   |
| FOO/BAR/BAZ/DDDDDDDDDD        |      4   |
| FOO/ZZZ/YYY/AAAAAAAAAA        |      1   |
| FOO/ZZZ/YYY/BBBBBBBBBB        |      2   |
--------------------------------------------

Answer 1

Let's try something like this(Oracle version 10g and higher):

SQL> with t1 as(
  2    select 'FOO/BAR/BAZ/AAAAAAAAAA' as RefNo,  1 as ID from dual union all
  3    select 'FOO/BAR/BAZ/BBBBBBBBBB',  1 from dual union all
  4    select 'FOO/BAR/BAZ/CCCCCCCCCC',  1 from dual union all
  5    select 'FOO/BAR/BAZ/DDDDDDDDDD',  1 from dual union all
  6    select 'FOO/ZZZ/YYY/AAAAAAAAAA',  1 from dual union all
  7    select 'FOO/ZZZ/YYY/BBBBBBBBBB',  1 from dual union all
  8    select 'FOO/ZZZ/YYY/CCCCCCCCCC',  1 from dual union all
  9    select 'FOO/ZZZ/YYY/DDDDDDDDDD',  1 from dual
 10  )
 11  select row_number() over(partition by ComPart order by DifPart) as id
 12       , RefNo
 13     From (select regexp_substr(RefNo, '[[:alpha:]]+$')   as DifPart
 14                , regexp_substr(RefNo, '([[:alpha:]]+/)+') as ComPart
 15                , RefNo
 16                , Id
 17             from t1
 18           ) q
 19  ;

        ID REFNO
---------- -----------------------
         1 FOO/BAR/BAZ/AAAAAAAAAA
         2 FOO/BAR/BAZ/BBBBBBBBBB
         3 FOO/BAR/BAZ/CCCCCCCCCC
         4 FOO/BAR/BAZ/DDDDDDDDDD
         1 FOO/ZZZ/YYY/AAAAAAAAAA
         2 FOO/ZZZ/YYY/BBBBBBBBBB
         3 FOO/ZZZ/YYY/CCCCCCCCCC
         4 FOO/ZZZ/YYY/DDDDDDDDDD

I think that actual updating the ID column wouldn't be a good idea. Every time you add new groups of data you would have to run the update statement again. The better way would be creating a view and you will see desired output every time you query it.

Answer 2

rownum can be used as an incrementing ID?

UPDATE legacy_table
    SET id = ROWNUM;

This will assign unique values to all records in the table. This link contains documentation about Oracle Pseudocolumn .

Answer 3

您可以运行以下命令：

update <table_name> set id = rownum where descr like 'FOO/BAR/BAZ/%'

Answer 4

This is pretty rough and I'm not sure if your RefNo is a single value column or you just made it like that for simplicity.

select 
    sub.RefNo
    row_number() over (order by sub.RefNo) + (select max(id) from TABLE),

from (
    select FOO+'/'+BAR+'/'+BAZ+'/'+OTHER as RefNo
    from TABLE
    group by FOO+'/'+BAR+'/'+BAZ+'/'+OTHER
) sub