Question

I have the following table named foo:

ID | KEY  | VAL
----------------
 1 | 47   | 97
 2 | 47   | 98
 3 | 47   | 99
 4 | 48   | 100
 5 | 48   | 101
 6 | 49   | 102

I want to run a select query and have the results show like this

UNIQUE_ID        | KEY  | ID1 | VAL1 | ID2 | VAL2 | ID3 | VAL3
--------------------------------------------------------------
47_1:97_2:98_3:99|  47  | 1   |  97  | 2   |  98  |  3  | 99
48_4:100_5:101   |  48  | 4   |  100 | 5   |  101 |     |  
49_6:102         |  49  | 6   |  102 |     |      |     | 

So, basically all rows with the same KEY get collapsed into 1 row. There can be anywhere from 1-3 rows per KEY value

Is there a way to do this in a sql query (without writing a stored procedure or scripts)?

If not, I could also work with the less desirable choice of

UNIQUE_ID        | KEY  | IDS   | VALS 
--------------------------------------------------------------
47_1:97_2:98_3:99|  47  | 1,2,3 | 97,98,99
48_4:100_5:101   |  48  | 4,5   | 100, 101 
49_6:102         |  49  | 6     | 102 

Thanks!

UPDATE:

Unfortunately my real-world problem seems to be much more difficult than this example, and I’m having trouble getting either example to work 🙁 My query is over 120 lines so it’s not very easy to post. It kind of looks like:

with v_table as (select ...), 
  v_table2 as (select foo from v_table where...), 
  v_table3 as (select foo from v_table where ...),
  ...
  v_table23 as (select foo from v_table where ...)
  select distinct (...) as "UniqueID", myKey, myVal, otherCol1, ..., otherCol18 
  from tbl1 inner join tbl2 on...
  ... 
  inner join tbl15 on ...

If I try any of the methods below it seems that I cannot do group-bys correctly because of all the other data being returned.
Ex:

with v_table as (select ...), 
  v_table2 as (select foo from v_table where...), 
  v_table3 as (select foo from v_table where ...),
  ...
  v_table23 as (select foo from v_table where ...)
  select "Unique ID",
   myKey, max(decode(id_col,1,id_col)) as id_1, max(decode(id_col,1,myVal)) as val_1,
   max(decode(id_col,2,id_col)) as id_2,max(decode(id_col,2,myVal)) as val_2,
   max(decode(id_col,3,id_col)) as id_3,max(decode(id_col,3,myVal)) as val_3
  from (
    select distinct (...) as "UniqueID", myKey, row_number() over (partition by myKey order by id) as id_col, id, myVal, otherCol1, ..., otherCol18 
    from tbl1 inner join tbl2 on...
    ... 
    inner join tbl15 on ...
  ) group by myKey;

Gives me the error: ORA-00979: not a GROUP BY expression

This is because I am selecting the UniqueID from the inner select. I will need to do this as well as select other columns from the inner table.

Any help would be appreciated!

Answer 1

You may try this

select key,
    max(decode(id_col,1,id_col)) as id_1,max(decode(id_col,1,val)) as val_1,
    max(decode(id_col,2,id_col)) as id_2,max(decode(id_col,2,val)) as val_2,
    max(decode(id_col,3,id_col)) as id_3,max(decode(id_col,3,val)) as val_3
from (
        select key, row_number() over (partition by key order by id) as id_col,id,val
        from your_table
    )
group by key