Merge two tables with update : Merge « Table « Oracle PL / SQL






Merge two tables with update

 
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>
SQL> select * from new_emp;

ID   FNAME      LNAME      START_DAT END_DATE      SALARY CITY
---- ---------- ---------- --------- --------- ---------- ----------
DESCRIPTION
---------------
01   Jason      Martin     25-JUL-96 25-JUL-06    1235.56 Toronto
Programmer

02   Alison     Mathews    21-MAR-76 21-FEB-86    6662.78 Vancouver
Tester

03   James      Smith      12-DEC-78 15-MAR-90    6545.78 Vancouver
Tester


ID   FNAME      LNAME      START_DAT END_DATE      SALARY CITY
---- ---------- ---------- --------- --------- ---------- ----------
DESCRIPTION
---------------
04   Celia      Rice       24-OCT-82 21-APR-99    2345.78 Vancouver
Manager

05   Robert     Black      15-JAN-84 08-AUG-98    2335.78 Vancouver
Tester

06   Linda      Green      30-JUL-87 04-JAN-96    4323.78 New York
Tester


ID   FNAME      LNAME      START_DAT END_DATE      SALARY CITY
---- ---------- ---------- --------- --------- ---------- ----------
DESCRIPTION
---------------
07   David      Larry      31-DEC-90 12-FEB-98    7898.78 New York
Manager

08   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 MATCHED THEN UPDATE SET e.salary = ne.salary;

8 rows merged.

SQL>
SQL>
SQL> -- clean the table
SQL> drop table new_emp;

Table dropped.

SQL> drop table emp
  2  /

Table dropped.

SQL>

   
  








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