Update statement for multiple records

Question

i have table a and table b
common col in both the tables is emp_id
in table b i have district_id
which i want to update in table a.... column district_id for all the employees
how to write update statement for this
Edited by: user10873676 on Oct 17, 2011 8:00 AM

Answer 1

Based on your current description, we have something like this...
SQL> create table a (emp_id number)
  2  /
Table created.
SQL>
SQL> create table b (emp_id number, district_id number)
  2  /
Table created.
SQL>
SQL> insert into a (emp_id)
  2  select rownum from dual connect by rownum <= 10
  3  /
10 rows created.
SQL>
SQL> insert into b (emp_id, district_id)
  2  select rownum, 10-rownum from dual connect by rownum <= 10
  3  /
10 rows created.
SQL>
SQL> update b
  2  set district_id = 1
  3  /
10 rows updated.
SQL>
SQL> select * from a;
    EMP_ID
         1
         2
         3
         4
         5
         6
         7
         8
         9
        10
10 rows selected.
SQL> select * from b;
    EMP_ID DISTRICT_ID
         1           1
         2           1
         3           1
         4           1
         5           1
         6           1
         7           1
         8           1
         9           1
        10           1
10 rows selected.Which I'm sure is NOT what you want as the update on table b has nothing to do with table a, and we have no idea what the district_id should be updated with.