如何在sql中的oracle数据库表中从月份到月份名称中选择值

Question

I want to my database table date column to month, and wanted to calculate the data from month to month But, i getting this error again and again

SQL> desc fac_cus_chd
 Name                                      Null?    Type
 ----------------------------------------- -------- ----------------------------
 FDC                                       NOT NULL VARCHAR2(9)
 WHDATE                                    NOT NULL DATE
 SL_NO                                     NOT NULL NUMBER(3)
 ITEMCODE                                  NOT NULL VARCHAR2(11)
 DECCODE                                   NOT NULL VARCHAR2(15)
 GRADE                                     NOT NULL VARCHAR2(1)
 QTY                                       NOT NULL NUMBER(9,2)
 UNIT                                      NOT NULL VARCHAR2(6)
 CARTON                                             VARCHAR2(5)
 UPRICE                                             NUMBER(9,2)
 UPT                                                VARCHAR2(1)
 CARTON_DET                                         VARCHAR2(5)

SQL> select SUM(QTY)
     from fac_cus_chd
     where whdate between to_date(to_char('01-JAN-2019', 'DD-MM-YYYY'), 'Month') AND  to_date(to_char('31-DEC-2019', 'DD-MM-YYYY') ;
  2  /
select to_date(to_char('WHDATE', 'DD-MM-YYYY'), 'Month') from fac_cus_chd
                       *
  ERROR at line 1:
  ORA-01722: invalid number
 SQL>

I want o have value like

Month         Qty 
Jan           200000
Feb           33,0000
Mar           34,0000 
APR            32293
May           242434
JUN            24242
JUL             24234
AUG            232423
SEP            242432
OCT            232342
NOV           33423
DEC           3233333 

Answer 1

Remove the quotes enclosing WHDATE . Also TO_DATE() doesnt convert the column directly but reads the data in the format given like you have DD-MM-YYYY below this ensures the data is read like this and converted to default date format of oracle

     TO_DATE(WHDATE, 'DD-MM-YYYY')


     TO_CHAR(WHDATE, 'MON')
       //this will give the desired

Answer 2

I think the solution would be something like that

with fac_cus_chd as(
select to_date('01-01-2019', 'DD-MM-YYYY') as whdate, 10 as qty from dual union all
select to_date('01-02-2019', 'DD-MM-YYYY') as whdate, 30 as qty from dual union all
select to_date('01-03-2019', 'DD-MM-YYYY') as whdate, 5 as qty from dual union all
select to_date('01-04-2019', 'DD-MM-YYYY') as whdate, 10 as qty from dual union all
select to_date('01-07-2019', 'DD-MM-YYYY') as whdate, 2 as qty from dual union all
select to_date('01-09-2019', 'DD-MM-YYYY') as whdate, 4 as qty from dual union all
select to_date('01-10-2019', 'DD-MM-YYYY') as whdate, 5 as qty from dual union all
select to_date('25-10-2019', 'DD-MM-YYYY') as whdate, 8 as qty from dual union all
select to_date('01-11-2019', 'DD-MM-YYYY') as whdate, 2 as qty from dual union all
select to_date('01-12-2019', 'DD-MM-YYYY') as whdate, 3 as qty from dual union all
select to_date('20-12-2019', 'DD-MM-YYYY') as whdate, 7 as qty from dual
)

    select to_char(trunc(whdate, 'MON'), 'Mon') as month_name
         , sum(qty) as quantity
      from fac_cus_chd
     where trunc(WHDATE, 'MON') between to_date('01-01-2019', 'DD-MM-YYYY')
                                    and to_date('31-12-2019', 'DD-MM-YYYY')
  group by trunc(whdate, 'MON')
  order by trunc(whdate, 'MON')

you could then apply ordering etc

MONTH_NAME  QUANTITY
Jan     10
Feb     30
Mar     5
Apr     10
Jul     2
Sep     4
Oct     13
Nov     2
Dec     10
9 rows

dbfiddle