Delete rows on basis of other table

Question

I am trying to delete records from table PS_BUN_CM on basis of table PS_BUN_UPDATE ...
below is the select statment which i want to convert to delete ... Please help
select *  FROM PS_BUN_CM a
inner join PS_BUN_UPDATE c on a.MAP_ID = c.MAP_ID
where a.ps_map_id in ('2400') and (a.las_name = 'NA' or a.las_name = 'na')and (c.LAS_NAME <> '  ');  

Answer 1

Not sure, how it is deleting all rows at your end. Please see below test
create table PS_BUN_CM(MAP_ID number,PS_MAP_ID varchar2(10),las_name varchar2(100))
Insert into PS_BUN_CM(MAP_ID, PS_MAP_ID, LAS_NAME)
Values(100, '10', 'abc')
Insert into PS_BUN_CM(MAP_ID, PS_MAP_ID, LAS_NAME)
Values(100, '100', 'NA')
Insert into PS_BUN_CM(MAP_ID, PS_MAP_ID, LAS_NAME)
Values(100, '100', 'na')
Insert into PS_BUN_CM(MAP_ID, PS_MAP_ID, LAS_NAME)
Values(1000000, '10022', 'na')
Insert into PS_BUN_CM(MAP_ID, PS_MAP_ID, LAS_NAME)
Values(100, '2400', 'na')
COMMIT
SQL> select * from ps_bun_cm;
    MAP_ID PS_MAP_ID  LAS_NAME
    100    10         abc
    100    100        NA
    100    100        na
   1000000 10022      na
    100    2400       na
SQL>
create table PS_BUN_UPDATE(MAP_ID number,las_name varchar2(100))
Insert into PS_BUN_UPDATE(MAP_ID, LAS_NAME)
Values(100, 'xyz')
Insert into PS_BUN_UPDATE(MAP_ID, LAS_NAME)
Values(100, '  ') 
COMMIT
SQL> select a.*,length(las_name)  from ps_bun_update a;
    MAP_ID  LAS_NAME   LENGTH(A.LAS_NAME)
    100     xyz           3
    100                   2
SQL>
SQL>select a.* from PS_BUN_CM a
  2 inner join PS_BUN_UPDATE c on a.map_id=c.map_id
  3 where a.ps_map_id in('2400') and (a.las_name='NA' or a.las_name='na')
  4 and c.las_name='  ';
    MAP_ID  PS_MAP_ID LAS_NAME
    100       2400     na
SQL> select * from     ps_bun_cm a
  2  where exists(select 1 from ps_bun_update c
  3               where a.map_id=c.map_id
  4               and a.ps_map_id in('2400')
  5               and (a.las_name='NA' or a.las_name='na')
  6               and c.las_name='  '
  7               ) ;
    MAP_ID  PS_MAP_ID  LAS_NAME
       100       2400   na
SQL> ed
Wrote file afiedt.buf
  1  delete from     ps_bun_cm a
  2  where exists(select 1 from ps_bun_update c
  3               where a.map_id=c.map_id
  4               and a.ps_map_id in('2400')
  5               and (a.las_name='NA' or a.las_name='na')
  6               and c.las_name='  '
  7*              )
SQL> /
1 row deleted.
SQL> select * from PS_BUN_CM;
    MAP_ID PS_MAP_ID  LAS_NAME
     100   10         abc
     100   100        NA
     100   100        na
   1000000 10022      na
SQL>