How to update One table column values with another table's column values? [duplicate]

This question already has answers here: Update rows in one table with da开发者_Python百科ta from another table based on one column in each being equal (5 answers) Closed 9 years ago.

i have table called Student with columns uniquename, age,department,city,Homecountry and another table called Employee with columns uniquename, exp,qualification, Homecountry.

now i want to update Student table's department column with Employee table's qualification column values under the where condition Student.uniquename = Employee.uniquename and Student.Homecountry = Employee.Homecountry.

please help me to write the update statement.

---

This kind of query is called a correlated sub query. For your requirement, the query would be as below....

update students s
  set s.department = (
          select e.qualification
            from employee e
            where s.uniquename = e.uniquename 
              and s.Homecountry = e.Homecountry
       );

updating this post based on your replies below.

Again, going forward, always post the create table and insert statements (and the expected results) to reproduce your case. If you don't see the expected results or if you see an erro when you execute the query, post the exact message instead of just saying "not working". Here is the results of my sqlplus session.

---create table and insert statements

create table student(
     name varchar2(20),
     age  number,
     department varchar2(3),
     HomeCountry varchar2(10)
    );

Table created.

create table employee5(
     name varchar2(20),
     exp  number,
     qualification varchar2(3),
     homecountry varchar2(10)
   );

Table created.

insert into student values ('Mohan',25,'EEE','India');
insert into student values ('Raja',27,'EEE','India');
insert into student values ('Ahamed',26,'ECE','UK');
insert into student values ('Gokul',25,'IT','USA');
commit;

insert into employee5 values ('Mohan',25,'ECE','India');
insert into employee5 values ('Raja',24,'IT','India');
insert into employee5 values ('Palani',26,'ECE','USA');
insert into employee5 values ('Sathesh',29,'CSE','CANADA');
insert into employee5 values ('Ahamed',28,'ECE','UK');
insert into employee5 values ('Gokul',29,'EEE','USA');
commit;

Before updating the data...

SQL> select * from student;

NAME                        AGE DEP HOMECOUNTR
-------------------- ---------- --- ----------
Mohan                        25 EEE India
Raja                         27 EEE India
Ahamed                       26 ECE UK
Gokul                        25 IT  USA

SQL> select * from employee5;

NAME                        EXP QUA HOMECOUNTR
-------------------- ---------- --- ----------
Mohan                        25 ECE India
Raja                         24 IT  India
Palani                       26 ECE USA
Sathesh                      29 CSE CANADA
Ahamed                       28 ECE UK
Gokul                        29 EEE USA

Update statement and results

  1  update student s set s.age =
  2     ( select e.exp
  3          from employee5 e
  4          where e.name = s.name
  5            and e.homecountry = s.homecountry
  6*    )
SQL> /

4 rows updated.

SQL> select * from student;

NAME                        AGE DEP HOMECOUNTR
-------------------- ---------- --- ----------
Mohan                        25 EEE India
Raja                         24 EEE India
Ahamed                       28 ECE UK
Gokul                        29 IT  USA

SQL> commit;

Commit complete.

---

update student s 
   set s.age = (select e.exp 
                  from employee5 e 
                  where e.name = s.name 
                    and e.homecountry = s.homecountry  
                    and rownum < 2
               )
where s.age in (select age from employee5)

It wont show the message subquery returns more than one record