Getting a 'Invalid Number' Error

Question

when i try to run the following code I get a 'ORA-01722 Number Error' and I can;t seem to figure out what the issue is.
the statement is a bit long so please bare with me:
select
       FN,
       LN,
       P_ID,
       Pitch_Count,
       max(case when zone=1 then results end) as Zone_1,
       max(case when zone=2 then results end) as Zone_2,
       max(case when zone=3 then results end) as Zone_3,
       max(case when zone=4 then results end) as Zone_4,
       max(case when zone=5 then results end) as Zone_5,
       max(case when zone=6 then results end) as Zone_6,
       max(case when zone=7 then results end) as Zone_7,
       max(case when zone=8 then results end) as Zone_8,
       max(case when zone=9 then results end) as Zone_9,     
       max(case when zone='A' then results end) as Zone_A,
       max(case when zone='B' then results end) as Zone_B,
       max(case when zone='C' then results end) as Zone_C,
       max(case when zone='D' then results end) as Zone_D,
       max(case when zone='E' then results end) as Zone_E,
       max(case when zone='F' then results end) as Zone_F,
       max(case when zone='G' then results end) as Zone_G,
       max(case when zone='H' then results end) as Zone_H,
       max(case when zone='I' then results end) as Zone_I,
       max(case when zone='J' then results end) as Zone_J,
       max(case when zone='K' then results end) as Zone_K,
       max(case when zone='L' then results end) as Zone_L,
       max(case when zone='M' then results end) as Zone_M,
       max(case when zone='N' then results end) as Zone_N,
       max(case when zone='O' then results end) as Zone_O,
       max(case when zone='P' then results end) as Zone_P
from   (
       select fn, ln, p_id, /*vs,*/ pitch_count, zone,
              '"F'||sum(decode(pitch_type,'F',1,0))
              ||','||
              'B"'||sum(decode(pitch_type,'B',1,0))
       as results
       from (
            select
              ev.pitcher_moniker as fn,
              ev.pitcher_last_name as ln,
             /* case
              when ev.event_prop_bats_left = 'y'
              then 'vs.Left'
              else
              'vs.Right'
              end as vs,*/
              ev.pitcher_id_1032 as p_id,
              decode(
              p.zone,      
              22, 1,
              23, 2,
              24, 3,
              32, 4,
              33, 5,
              34, 6,
              42, 7,
              43, 8,
              44, 9,
              11, 'A',
              12, 'B',
              13, 'C',
              14, 'D',
              15, 'E',
              21, 'F',
              25, 'G',
              31, 'H',
              35, 'I',
              41, 'J',
              45, 'K',
              51, 'L',
              52, 'M',
              53, 'N',
              54, 'O',
              55, 'P'
              ) as zone,
              decode(
              p.pitch_type_id,
              1,'F',
              9,'F',
              7,'U',
              'B'
              ) as pitch_type,
              Case
              When p.balls = 0 and p.strikes = 0
                 Then 'First Pitch'
              When p.balls = 3 and p.strikes = 2
                 Then 'Full Count'
              Else To_char (p.balls) || '-' || to_char (p.strikes) || ' Count'
              End as pitch_count     
              from  customer_data.baseball_tvl_pitches p,
                    customer_data.baseball_tvl_events ev
              where ev.event_number = p.event_number
              and ev.game_code_1032 = p.game_code_1032
              and ev.season = 2008
              and p.game_type_id = 1
              and p.game_code_1032 = ev.game_code_1032
              and p.zone in (
                             11,12,13,14,15,
                             21,22,23,24,25,
                             31,32,33,34,35,
                             41,42,43,44,45,
                             51,52,53,54,55
              order by
                  ev.pitcher_id_1032
    group by fn, ln, /*vs,*/ p_id, zone, pitch_count
    order by p_id, decode(pitch_count,'First Pitch','0--','Full Count','999',pitch_count) asc, zone
group by fn, ln, p_id, pitch_count
order by ln, decode(pitch_count,'First Pitch','0--','Full Count','999',pitch_count) asc;

Answer 1

decode(
              p.zone,      
              22, 1,
              23, 2,
              24, 3,
              32, 4,
              33, 5,
              34, 6,
              42, 7,
              43, 8,
              44, 9,
              11, 'A',
              12, 'B',
              13, 'C',
              14, 'D',
              15, 'E',
              21, 'F',
              25, 'G',
              31, 'H',
              35, 'I',
              41, 'J',
              45, 'K',
              51, 'L',
              52, 'M',
              53, 'N',
              54, 'O',
              55, 'P'
              ) as zone,The first returned value of a decode statement determines the return datatype. In your example your first returned value is 1 which is a number, so when it get's down to 'A' it is trying to implicitly convert that string to a number and failing. You should only deal with one datatype so in this case you would be best to surround all your returned numbers (1,2,3,4,5,6,7,8 and 9) with single quotes.