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>
1. | Merge table into another table | ||
2. | Merge two tables when matched or not matched | ||
3. | Merge two tables with update |