Merge two tables and map columns
SQL>
SQL> -- create demo table
SQL> create table emp(
2 ID VARCHAR2(4 BYTE) NOT NULL,
3 fname VARCHAR2(10 BYTE),
4 lname VARCHAR2(10 BYTE),
5 Start_Date DATE,
6 End_Date DATE,
7 Salary Number(8,2),
8 City VARCHAR2(10 BYTE),
9 Description VARCHAR2(15 BYTE)
10 )
11 /
Table created.
SQL>
SQL> -- prepare data
SQL> insert into emp(ID, fname, lname, Start_Date, End_Date, Salary, City, Description)
2 values ('01','Jason', 'Martin', to_date('19960725','YYYYMMDD'), to_date('20060725','YYYYMMDD'), 1234.56, 'Toronto', 'Programmer')
3 /
1 row created.
SQL> insert into emp(ID, fname, lname, Start_Date, End_Date, Salary, City, Description)
2 values('02','Alison', 'Mathews', to_date('19760321','YYYYMMDD'), to_date('19860221','YYYYMMDD'), 6661.78, 'Vancouver','Tester')
3 /
1 row created.
SQL> insert into emp(ID, fname, lname, Start_Date, End_Date, Salary, City, Description)
2 values('03','James', 'Smith', to_date('19781212','YYYYMMDD'), to_date('19900315','YYYYMMDD'), 6544.78, 'Vancouver','Tester')
3 /
1 row created.
SQL> insert into emp(ID, fname, lname, Start_Date, End_Date, Salary, City, Description)
2 values('04','Celia', 'Rice', to_date('19821024','YYYYMMDD'), to_date('19990421','YYYYMMDD'), 2344.78, 'Vancouver','Manager')
3 /
1 row created.
SQL> insert into emp(ID, fname, lname, Start_Date, End_Date, Salary, City, Description)
2 values('05','Robert', 'Black', to_date('19840115','YYYYMMDD'), to_date('19980808','YYYYMMDD'), 2334.78, 'Vancouver','Tester')
3 /
1 row created.
SQL> insert into emp(ID, fname, lname, Start_Date, End_Date, Salary, City, Description)
2 values('06','Linda', 'Green', to_date('19870730','YYYYMMDD'), to_date('19960104','YYYYMMDD'), 4322.78,'New York', 'Tester')
3 /
1 row created.
SQL> insert into emp(ID, fname, lname, Start_Date, End_Date, Salary, City, Description)
2 values('07','David', 'Larry', to_date('19901231','YYYYMMDD'), to_date('19980212','YYYYMMDD'), 7897.78,'New York', 'Manager')
3 /
1 row created.
SQL> insert into emp(ID, fname, lname, Start_Date, End_Date, Salary, City, Description)
2 values('08','James', 'Cat', to_date('19960917','YYYYMMDD'), to_date('20020415','YYYYMMDD'), 1232.78,'Vancouver', 'Tester')
3 /
1 row created.
SQL>
SQL>
SQL>
SQL> -- display data in the table
SQL> select * from emp
2 /
ID FNAME LNAME START_DAT END_DATE SALARY CITY
---- ---------- ---------- --------- --------- ---------- ----------
DESCRIPTION
---------------
01 Jason Martin 25-JUL-96 25-JUL-06 1234.56 Toronto
Programmer
02 Alison Mathews 21-MAR-76 21-FEB-86 6661.78 Vancouver
Tester
03 James Smith 12-DEC-78 15-MAR-90 6544.78 Vancouver
Tester
ID FNAME LNAME START_DAT END_DATE SALARY CITY
---- ---------- ---------- --------- --------- ---------- ----------
DESCRIPTION
---------------
04 Celia Rice 24-OCT-82 21-APR-99 2344.78 Vancouver
Manager
05 Robert Black 15-JAN-84 08-AUG-98 2334.78 Vancouver
Tester
06 Linda Green 30-JUL-87 04-JAN-96 4322.78 New York
Tester
ID FNAME LNAME START_DAT END_DATE SALARY CITY
---- ---------- ---------- --------- --------- ---------- ----------
DESCRIPTION
---------------
07 David Larry 31-DEC-90 12-FEB-98 7897.78 New York
Manager
08 James Cat 17-SEP-96 15-APR-02 1232.78 Vancouver
Tester
8 rows selected.
SQL>
SQL>
SQL> create table new_emp as select * from emp;
Table created.
SQL>
SQL> update new_emp set salary = salary +1;
8 rows updated.
SQL> update new_emp set id = id +1;
8 rows updated.
SQL>
SQL> select * from new_emp;
ID FNAME LNAME START_DAT END_DATE SALARY CITY
---- ---------- ---------- --------- --------- ---------- ----------
DESCRIPTION
---------------
2 Jason Martin 25-JUL-96 25-JUL-06 1235.56 Toronto
Programmer
3 Alison Mathews 21-MAR-76 21-FEB-86 6662.78 Vancouver
Tester
4 James Smith 12-DEC-78 15-MAR-90 6545.78 Vancouver
Tester
ID FNAME LNAME START_DAT END_DATE SALARY CITY
---- ---------- ---------- --------- --------- ---------- ----------
DESCRIPTION
---------------
5 Celia Rice 24-OCT-82 21-APR-99 2345.78 Vancouver
Manager
6 Robert Black 15-JAN-84 08-AUG-98 2335.78 Vancouver
Tester
7 Linda Green 30-JUL-87 04-JAN-96 4323.78 New York
Tester
ID FNAME LNAME START_DAT END_DATE SALARY CITY
---- ---------- ---------- --------- --------- ---------- ----------
DESCRIPTION
---------------
8 David Larry 31-DEC-90 12-FEB-98 7898.78 New York
Manager
9 James Cat 17-SEP-96 15-APR-02 1233.78 Vancouver
Tester
8 rows selected.
SQL>
SQL> --Merging Rows Using MERGE
SQL> --merge rows from one table into another
SQL>
SQL> MERGE INTO emp e
2 USING new_emp ne ON (e.id = ne.id)
3 WHEN NOT MATCHED THEN
4 INSERT (e.id, e.fname, e.lname, e.description, e.salary)VALUES(ne.id,ne.fna
me,ne.lname,ne.description,ne.salary);
8 rows merged.
SQL>
SQL> -- clean the table
SQL> drop table new_emp;
Table dropped.
SQL> drop table emp
2 /
Table dropped.
SQL>
SQL>
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