Re: get the column_name of the maximum value for a row

From: Michel Cadot <micadot{at}altern{dot}org>
Date: Fri, 18 Sep 2009 17:19:09 +0200
Message-ID: <4ab3a4ee$0$25139$426a74cc_at_news.free.fr>

"ddf" <oratune_at_msn.com> a écrit dans le message de news: 9adadbc9-22c9-4138-90e5-9f3647c28d32_at_h30g2000vbr.googlegroups.com... On Sep 18, 8:36 am, Mark D Powell <Mark.Pow..._at_eds.com> wrote:
> On Sep 18, 7:44 am, Ninja Li <nickli2..._at_gmail.com> wrote:
>
>
>
>
>
> > On Sep 18, 12:18 am, "Michel Cadot" <micadot{at}altern{dot}org> wrote:
>
> > > "Ninja Li" <nickli2..._at_gmail.com> a écrit dans le message de news:
> > > 328aa22c-967d-4ac1-b453-8a73b3147..._at_33g2000vbe.googlegroups.com...
> > > | Hi,
> > > |
> > > | I want to get the column_name of the maximum value of a row. To
> > > | simplify, the table has the following format and values, with
> > > | input_date being unique. The columns evaluated are the "value_"
> > > | columns.
> > > |
> > > | input_date value_1 value_2 value_3 ** maximum
> > > | value ** maximum value_column
> > > | 01-SEP-09 10 15 8
> > > | 15 value_1
> > > | 02-SEP-09 12 5 18
> > > | 18 value_3
> > > | 03-SEP-09 9 12 12
> > > | 12 value_2
> > > | ...........
> > > |
> > > | The desired output is:
> > > | 01-SEP-09 15 value_1
> > > | 02-SEP-09 18 value_3
> > > | 03-SEP-09 12 value_3
> > > | ..........
> > > |
> > > | Is the problem solvable using plain SQL? Or do I need to use PL/
> > > | SQL? The database is Oracle 9i.
> > > |
> > > | Thanks in advance.
> > > |
> > > | Nick
> > > |
> > > |
> > > |
>
> > > Use DECODE.
> > > What should be the value if 2 or more columns have the highest value?
>
> > > Regards
> > > Michel
>
> > Thanks Michel. If two or more column have the highest value, the
> > column name withe lowest value will be picked. For example, value_2
> > column will be selected over value_3.
>
> > Could you also elaborate on how to use the DECODE?
>
> > Nick- Hide quoted text -
>
> > - Show quoted text -
>
> I was going to say use a CASE statement in your SELECT statement but
> decode is basically the same functionality. when colA > colB and colA
>
> > colC then 'colA '||value_a
>
> You can find the full syntax of the CASE and DECODE in the SQL Manual.
>
> Decode with exampleshttp://download.oracle.com/docs/cd/B10501_01/server.920/a96540/functi...
>
> CASE statement with examplehttp://download.oracle.com/docs/cd/B10501_01/server.920/a96540/expres...
>
> If you did not need to know the column you could use the GREATEST
> function.
>
> > set echo on
> > select * from marktest4;
>
> FLD1 FLD2 FLD3
> ---------- ---------- ----------
> 7 8 9
> 9 8 7
>
> > _at_t19
> > select case when fld1 > fld2 and fld1 > fld3 then 'FLD1 '||fld1
> 2 when fld2 > fld1 and fld2 > fld3 then 'FLD2 '||fld2
> 3 when fld3 > fld1 and fld3 > fld2 then 'FLD3 '||fld3
> 4 else 'Error' end "VALUE"
> 5 from marktest4
> 6 /
>
> VALUE
> ---------------------------------------------
> FLD3 9
> FLD1 9
>
> HTH -- Mark D Powell --- Hide quoted text -
>
> - Show quoted text -

For your example the code isn't 'pretty':

SQL> create table value_test(

  2  input_date date primary key,
  3  value_1 number,
  4  value_2 number,
  5  value_3 number

  6 );

Table created.

SQL>
SQL> insert all
  2 into value_test
  3 values(to_date('01-SEP-09','DD-MON-RR'), 10, 15, 8)   4 into value_test
  5 values(to_date('02-SEP-09','DD-MON-RR'), 12, 5, 18)   6 into value_test
  7 values(to_date('03-SEP-09','DD-MON-RR'), 9, 12, 12)   8 into value_test
  9 values(to_date('04-SEP-09','DD-MON-RR'), 19, 12, 12)  10 into value_test
 11 values(to_date('05-SEP-09','DD-MON-RR'), 8, 1, 2)  12 into value_test
 13 values(to_date('06-SEP-09','DD-MON-RR'), 9, 12, 4)  14 into value_test
 15 values(to_date('07-SEP-09','DD-MON-RR'), 38, 42, 12)  16 into value_test
 17 values(to_date('08-SEP-09','DD-MON-RR'), 89, 89, 89)  18 into value_test
 19 values(to_date('09-SEP-09','DD-MON-RR'), 9, 17, 22)  20 into value_test
 21 values(to_date('10-SEP-09','DD-MON-RR'), 12, 12, 17)  22 select * From dual;

10 rows created.

SQL>
SQL> commit;

Commit complete.

SQL>
SQL> select input_date,
  2 case when value_1 < value_2 and value_2 < value_3 then value_3
  3 when value_3 < value_2 and value_2 < value_1 then value_1
  4 when value_3 < value_1 and value_1 < value_2 then value_2
  5 when value_3 < value_2 and value_2 = value_1 then value_1
  6 when value_3 = value_2 and value_2 < value_1 then value_2
  7 when value_3 > value_1 and value_1 > value_2 then value_3
  8 when value_3 = value_2 and value_2 > value_1 then value_2
  9 when value_1 > value_2 and value_2 < value_3 then value_1
 10 when value_1 = value_2 and value_2 = value_3 then value_1
 11 when value_1 = value_2 and value_2 < value_3 then value_3

 12         end max_val,
 13         case when value_1 < value_2 and value_2 < value_3 then
'value_3'
 14              when value_3 < value_2 and value_2 < value_1 then
'value_1'
 15              when value_3 < value_1 and value_1 < value_2 then
'value_2'
 16              when value_3 < value_2 and value_2 = value_1 then
'value_1'
 17              when value_3 = value_2 and value_2 < value_1 then
'value_2'
 18              when value_3 > value_1 and value_1 > value_2 then
'value_3'
 19              when value_3 = value_2 and value_2 > value_1 then
'value_2'
 20              when value_1 > value_2 and value_2 < value_3 then
'value_1'
 21              when value_1 = value_2 and value_2 = value_3 then
'value_1'
 22              when value_1 = value_2 and value_2 < value_3 then
'value_3'
 23         end max_val_col

 24 from value_test;

INPUT_DATE MAX_VAL MAX_VAL

-------------------- ---------- -------
01-SEP-2009 00:00:00         15 value_2
02-SEP-2009 00:00:00         18 value_3
03-SEP-2009 00:00:00         12 value_2
04-SEP-2009 00:00:00         12 value_2
05-SEP-2009 00:00:00          8 value_1
06-SEP-2009 00:00:00         12 value_2
07-SEP-2009 00:00:00         42 value_2
08-SEP-2009 00:00:00         89 value_1
09-SEP-2009 00:00:00         22 value_3
10-SEP-2009 00:00:00         17 value_3

10 rows selected.

SQL> but it does work.

David Fitzjarrell

---

What I had in mind is the following one:

SQL> select input_date,

  2         decode(greatest(value_1,value_2,value_3),
  3                value_1,'VALUE_1',
  4                value_2,'VALUE_2',
  5                        'VALUE_3') col,
  6         greatest(value_1,value_2,value_3) value

  7 from value_test
  8 order by 1
  9 /
INPUT_DATE COL VALUE

----------- ------- ----------
01-SEP-2009 VALUE_2         15
02-SEP-2009 VALUE_3         18
03-SEP-2009 VALUE_2         12
04-SEP-2009 VALUE_1         19
05-SEP-2009 VALUE_1          8
06-SEP-2009 VALUE_2         12
07-SEP-2009 VALUE_2         42
08-SEP-2009 VALUE_1         89
09-SEP-2009 VALUE_3         22
10-SEP-2009 VALUE_3         17

10 rows selected.

Regards
Michel Received on Fri Sep 18 2009 - 10:19:09 CDT