Oracle PL/SQL/Insert Delete Update/Delete Subquery
Writing a DELETE Statement Containing a Subquery
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SQL> SQL> -- create demo table SQL> create table Employee(
2 ID VARCHAR2(4 BYTE) NOT NULL, 3 First_Name VARCHAR2(10 BYTE), 4 Last_Name 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 Employee(ID, First_Name, Last_Name, 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 Employee(ID, First_Name, Last_Name, 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 Employee(ID, First_Name, Last_Name, 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 Employee(ID, First_Name, Last_Name, 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 Employee(ID, First_Name, Last_Name, 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 Employee(ID, First_Name, Last_Name, 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 Employee(ID, First_Name, Last_Name, 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 Employee(ID, First_Name, Last_Name, 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 Employee
2 /
ID FIRST_NAME LAST_NAME START_DATE END_DATE SALARY CITY DESCRIPTION
---------- ---------- ----------- ----------- ---------- ---------- ---------------
01 Jason Martin 1996-JUL-25 2006-JUL-25 1234.56 Toronto Programmer 02 Alison Mathews 1976-MAR-21 1986-FEB-21 6661.78 Vancouver Tester 03 James Smith 1978-DEC-12 1990-MAR-15 6544.78 Vancouver Tester 04 Celia Rice 1982-OCT-24 1999-APR-21 2344.78 Vancouver Manager 05 Robert Black 1984-JAN-15 1998-AUG-08 2334.78 Vancouver Tester 06 Linda Green 1987-JUL-30 1996-JAN-04 4322.78 New York Tester 07 David Larry 1990-DEC-31 1998-FEB-12 7897.78 New York Manager 08 James Cat 1996-SEP-17 2002-APR-15 1232.78 Vancouver Tester 8 rows selected. SQL> SQL> SQL> -- Writing a DELETE Statement Containing a Subquery SQL> SQL> DELETE FROM employee
2 WHERE salary > 3 (SELECT AVG(salary) 4 FROM employee);
4 rows deleted. SQL> SQL> select * from employee; ID FIRST_NAME LAST_NAME START_DATE END_DATE SALARY CITY DESCRIPTION
---------- ---------- ----------- ----------- ---------- ---------- ---------------
01 Jason Martin 1996-JUL-25 2006-JUL-25 1234.56 Toronto Programmer 04 Celia Rice 1982-OCT-24 1999-APR-21 2344.78 Vancouver Manager 05 Robert Black 1984-JAN-15 1998-AUG-08 2334.78 Vancouver Tester 08 James Cat 1996-SEP-17 2002-APR-15 1232.78 Vancouver Tester SQL> SQL> -- clean the table SQL> drop table Employee
2 /
Table dropped. SQL> SQL>
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