create table tb(services varchar(10),b_flag int,b_PortCode int,POL_POD varchar(20),b_id int,PortCode int)
insert into tb values('xx',       0,      0 ,         'HK'     ,   0,     14) 
insert into tb values('xx',       1,      0 ,         'Guam'   ,   1,     19) 
insert into tb values('xx',       0,      19,         'Busan' ,   0,     21) 
insert into tb values('xx',       0,      19,         'Tacoma',   0,     16) 
insert into tb values('xx',       1,      0 ,         'Newark' ,   2,     26) 
insert into tb values('xx',       0,      26,         'GOGO' ,   0,     15)
go

update tb
set POL_POD = left('**********',t.b_id) + a.POL_POD
from tb a,(select * from tb where b_flag = 1) t
where a.b_portcode = t.portcode

select * from tb

drop table tb

/*
services   b_flag      b_PortCode  POL_POD              b_id        PortCode    
---------- ----------- ----------- -------------------- ----------- ----------- 
xx         0           0           HK                   0           14
xx         1           0           Guam                 1           19
xx         0           19          *Busan               0           21
xx         0           19          *Tacoma              0           16
xx         1           0           Newark               2           26
xx         0           26          **GOGO               0           15

（所影响的行数为 6 行）
*/