Oracle PL/SQL/Select Query/EXISTS

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Display the customer number and last name of all customers with no orders.

 
SQL>
SQL>
SQL> create table ord(
  2           order_no               integer          primary key
  3          ,cust_no                integer
  4          ,order_date             date not null
  5          ,total_order_price      number(7,2)
  6          ,deliver_date           date
  7          ,deliver_time           varchar2(7)
  8          ,payment_method         varchar2(2)
  9          ,emp_no                 number(3,0)
 10          ,deliver_name           varchar2(35)
 11          ,gift_message           varchar2(100)
 12  );
Table created.
SQL>
SQL>
SQL> insert into ord(order_no,cust_no,order_date,total_order_price,deliver_date,deliver_time,payment_method,emp_no,deliver_name,gift_message)
  2           values(1,1,"14-Feb-2002", 23.00, "14-Feb-2002", "12 noon", "CA",1, null, "Gift for wife");
1 row created.
SQL> insert into ord(order_no  ,cust_no ,order_date ,total_order_price ,deliver_date ,deliver_time ,payment_method ,emp_no,deliver_name ,gift_message )
  2           values(2,1,"14-Feb-2003", 510.98, "14-feb-2003", "5 pm", "NY",7, "Rose Ted", "Happy Valentines Day to Mother");
1 row created.
SQL> insert into ord(order_no  ,cust_no ,order_date ,total_order_price ,deliver_date ,deliver_time,payment_method ,emp_no,deliver_name ,gift_message )
  2           values(3, 2,"14-Feb-2004", 315.99, "14-feb-2004", "3 pm", "VS",2, "Ani Forest", "Happy Valentines Day to Father");
1 row created.
SQL> insert into ord(order_no  ,cust_no ,order_date ,total_order_price ,deliver_date ,deliver_time,payment_method ,emp_no,deliver_name ,gift_message )
  2           values(4, 2,"14-Feb-1999", 191.95, "14-feb-1999", "2 pm", "NJ",2, "O. John", "Happy Valentines Day");
1 row created.
SQL> insert into ord(order_no  ,cust_no ,order_date ,total_order_price ,deliver_date ,deliver_time,payment_method ,emp_no,deliver_name ,gift_message    )
  2           values(5, 6,"4-mar-2002", 101.95, "5-mar-2002", "2:30 pm", "MO"   , 2, "Cora", "Happy Birthday from John");
1 row created.
SQL> insert into ord(order_no  ,cust_no ,order_date ,total_order_price ,deliver_date ,deliver_time,payment_method ,emp_no,deliver_name ,gift_message )
  2           values(6, 9,"7-apr-2003", 221.95, "7-apr-2003", "3 pm", "MA", 2, "Sake Keith", "Happy Birthday from Joe" );
1 row created.
SQL> insert into ord(order_no  ,cust_no ,order_date ,total_order_price ,deliver_date ,deliver_time,payment_method ,emp_no,deliver_name ,gift_message )
  2           values(7, 9,"20-jun-2004", 315.95, "21-jun-2004", "12 noon", "BC", 2, "Jessica Li", "Happy Birthday from Jessica");
1 row created.
SQL> insert into ord(order_no  ,cust_no ,order_date ,total_order_price ,deliver_date ,deliver_time,payment_method ,emp_no,deliver_name ,gift_message )
  2           values (8, 12, "31-dec-1999", 135.95, "1-jan-2000", "12 noon", "DI",      3, "Larry", "Happy New Year from Lawrence");
1 row created.
SQL> insert into ord(order_no  ,cust_no ,order_date ,total_order_price ,deliver_date ,deliver_time,payment_method ,emp_no,deliver_name ,gift_message )
  2           values (9, 12, "26-dec-2003", 715.95, "2-jan-2004", "12 noon", "SK",7, "Did", "Happy Birthday from Nancy" );
1 row created.
SQL> insert into ord(order_no  ,cust_no ,order_date ,total_order_price ,deliver_date ,deliver_time,payment_method ,emp_no,deliver_name ,gift_message )
  2           values(10, 4, sysdate-1, 119.95, sysdate+2, "6:30 pm", "VG",2, "P. Jing", "Happy Valentines Day to Jason");
1 row created.
SQL> insert into ord(order_no  ,cust_no ,order_date ,total_order_price ,deliver_date ,deliver_time,payment_method ,emp_no,deliver_name ,gift_message )
  2           values(11, 2, sysdate, 310.00, sysdate+2, "3:30 pm", "DC",2, "C. Late", "Happy Birthday Day to Jack");
1 row created.
SQL> insert into ord(order_no  ,cust_no ,order_date ,total_order_price ,deliver_date ,deliver_time,payment_method ,emp_no,deliver_name ,gift_message)
  2           values(12, 7, sysdate-3, 121.95, sysdate-2, "1:30 pm", "AC",2, "W. Last", "Happy Birthday Day to You");
1 row created.
SQL> insert into ord(order_no  ,cust_no ,order_date ,total_order_price ,deliver_date ,deliver_time,payment_method ,emp_no,deliver_name ,gift_message)
  2           values(13, 7, sysdate, 211.95, sysdate-4, "4:30 pm", "CA",2, "J. Bond", "Thanks for hard working");
1 row created.
SQL>
SQL>
SQL> create table customer(
  2           cust_no                   integer                 primary key
  3          ,lastname                  varchar2(20)    not null
  4          ,firstname                 varchar2(15)    not null
  5          ,midinit                   varchar2(1)
  6          ,street                    varchar2(30)
  7          ,city                      varchar2(20)
  8          ,state                             varchar2(2)
  9          ,zip                               varchar2(5)
 10          ,zip_4                             varchar2(4)
 11          ,area_code                         varchar2(3)
 12          ,phone                             varchar2(8)
 13          ,company_name                      varchar2(50)
 14  );
Table created.
SQL>
SQL> insert into customer(cust_no,lastname,firstname,midinit,street,city,state,zip,zip_4,area_code,phone,company_name)
  2                values(1, "Allen", "Joe","J","10 Ave","London","CA","11111","1111","111", "111-1111","Big Company");
1 row created.
SQL> insert into customer(cust_no,lastname,firstname,midinit,street,city,state,zip,zip_4,area_code,phone,company_name)
  2                values(2,"Ward","Sue","W","20 Ave","New York","NY","44444","4444","444", "436-4444","B Company");
1 row created.
SQL> insert into customer(cust_no,lastname,firstname,midinit,street,city,state,zip,zip_4,area_code,phone,company_name)
  2                values(3,"Jason","Pure","J","50 St","Longli","CA","55555","5555","555", "234-4444","C Company");
1 row created.
SQL> insert into customer(cust_no,lastname,firstname,midinit,street,city,state,zip,zip_4,area_code,phone,company_name)
  2                values(4,"Bird","Jill", null,"30 St","Pais","NY","22222","2222","222", "634-7733","D Company");
1 row created.
SQL> insert into customer(cust_no,lastname,firstname,midinit,street,city,state,zip,zip_4,area_code,phone,company_name)
  2                values(5,"Hill","Carl","H","19 Drive","A Town","CA","66666","6566","666", "243-4243","E Company");
1 row created.
SQL> insert into customer(cust_no,lastname,firstname,midinit,street,city,state,zip,zip_4,area_code,phone,company_name)
  2                values(6,"Peter","Yari","P","38 Ave","Small City","NY","77777","7777","777", "454-5443","F Inc");
1 row created.
SQL> insert into customer(cust_no,lastname,firstname,midinit,street,city,state,zip,zip_4,area_code,phone,company_name)
  2                values(7,"Joe","Paula","J","78 St. Apt 3A","Queen City","NY","32322","2323","888", "664-4333","E Inc");
1 row created.
SQL> insert into customer(cust_no,lastname,firstname,midinit,street,city,state,zip,zip_4,area_code,phone,company_name)
  2                values(8,"Chili","Steve","C","38 Ave Apt 62","Mili","CA","88888","8888","787", "456-4566","G Inc");
1 row created.
SQL> insert into customer(cust_no,lastname,firstname,midinit,street,city,state,zip,zip_4,area_code,phone,company_name)
  2                values(9,"Mona","Joe","M","930 Ave933","Kansas City","MO","12345","1234","412", "456-4563","H Inc");
1 row created.
SQL> insert into customer(cust_no,lastname,firstname,midinit,street,city,state,zip,zip_4,area_code,phone,company_name)
  2                values(10,"Hack","Kisi","H","Kings Rd","Bellmore","NY","54321","3898","516", "767-5677","I Inc");
1 row created.
SQL> insert into customer(cust_no,lastname,firstname,midinit,street,city,state,zip,zip_4,area_code,phone,company_name)
  2                values(11,"Bill","Jose","B","12 Giant Rd.","Newton","NJ","23454","1234","958", "123-7367","J Associates");
1 row created.
SQL> insert into customer(cust_no,lastname,firstname,midinit,street,city,state,zip,zip_4,area_code,phone,company_name)
  2                values(12,"Taker","Lawrence","T","1 Sask Rd.","Camp","NJ","19191","3298","928", "123-7384","K Company");
1 row created.
SQL> insert into customer(cust_no,lastname,firstname,midinit,street,city,state,zip,zip_4,area_code,phone,company_name)
  2                values(13,"Richer","Doris","R","213 Easy Street","WarPease","RI","34343","2112","501", "123-7384","L Inc");
1 row created.
SQL> insert into customer( cust_no,lastname,firstname,midinit,street,city,state,zip,zip_4,area_code,phone,company_name)
  2                values(14,"Pete","Doris","P","9 Ave","New York","NY","45454","4222","112", "123-1234","M Company");
1 row created.
SQL>
SQL>
SQL>
SQL> select cust_no, lastname
  2    from customer c
  3    where not exists
  4    (select * from ord o where o.cust_no = c.cust_no);
   CUST_NO LASTNAME
---------- --------------------
         5 Hill
         8 Chili
         3 Jason
        10 Hack
        14 Pete
        13 Richer
        11 Bill
7 rows selected.
SQL>
SQL> drop table ord;
Table dropped.
SQL> drop table customer;
Table dropped.
SQL> --



Test the NOT EXISTS version

 
SQL> --Test the NOT EXISTS version
SQL>
SQL> create table customer(
  2           cust_no                   integer                 primary key
  3          ,lastname                  varchar2(20)    not null
  4          ,firstname                 varchar2(15)    not null
  5          ,midinit                   varchar2(1)
  6          ,street                    varchar2(30)
  7          ,city                      varchar2(20)
  8          ,state                             varchar2(2)
  9          ,zip                               varchar2(5)
 10          ,zip_4                             varchar2(4)
 11          ,area_code                         varchar2(3)
 12          ,phone                             varchar2(8)
 13          ,company_name                      varchar2(50)
 14  );
Table created.
SQL>
SQL> insert into customer(cust_no,lastname,firstname,midinit,street,city,state,zip,zip_4,area_code,phone,company_name)
  2                values(1, "Allen", "Joe","J","10 Ave","London","CA","11111","1111","111", "111-1111","Big Company");
1 row created.
SQL> insert into customer(cust_no,lastname,firstname,midinit,street,city,state,zip,zip_4,area_code,phone,company_name)
  2                values(2,"Ward","Sue","W","20 Ave","New York","NY","44444","4444","444", "436-4444","B Company");
1 row created.
SQL> insert into customer(cust_no,lastname,firstname,midinit,street,city,state,zip,zip_4,area_code,phone,company_name)
  2                values(3,"Jason","Pure","J","50 St","Longli","CA","55555","5555","555", "234-4444","C Company");
1 row created.
SQL> insert into customer(cust_no,lastname,firstname,midinit,street,city,state,zip,zip_4,area_code,phone,company_name)
  2                values(4,"Bird","Jill", null,"30 St","Pais","NY","22222","2222","222", "634-7733","D Company");
1 row created.
SQL> insert into customer(cust_no,lastname,firstname,midinit,street,city,state,zip,zip_4,area_code,phone,company_name)
  2                values(5,"Hill","Carl","H","19 Drive","A Town","CA","66666","6566","666", "243-4243","E Company");
1 row created.
SQL> insert into customer(cust_no,lastname,firstname,midinit,street,city,state,zip,zip_4,area_code,phone,company_name)
  2                values(6,"Peter","Yari","P","38 Ave","Small City","NY","77777","7777","777", "454-5443","F Inc");
1 row created.
SQL> insert into customer(cust_no,lastname,firstname,midinit,street,city,state,zip,zip_4,area_code,phone,company_name)
  2                values(7,"Joe","Paula","J","78 St. Apt 3A","Queen City","NY","32322","2323","888", "664-4333","E Inc");
1 row created.
SQL> insert into customer(cust_no,lastname,firstname,midinit,street,city,state,zip,zip_4,area_code,phone,company_name)
  2                values(8,"Chili","Steve","C","38 Ave Apt 62","Mili","CA","88888","8888","787", "456-4566","G Inc");
1 row created.
SQL> insert into customer(cust_no,lastname,firstname,midinit,street,city,state,zip,zip_4,area_code,phone,company_name)
  2                values(9,"Mona","Joe","M","930 Ave933","Kansas City","MO","12345","1234","412", "456-4563","H Inc");
1 row created.
SQL> insert into customer(cust_no,lastname,firstname,midinit,street,city,state,zip,zip_4,area_code,phone,company_name)
  2                values(10,"Hack","Kisi","H","Kings Rd","Bellmore","NY","54321","3898","516", "767-5677","I Inc");
1 row created.
SQL> insert into customer(cust_no,lastname,firstname,midinit,street,city,state,zip,zip_4,area_code,phone,company_name)
  2                values(11,"Bill","Jose","B","12 Giant Rd.","Newton","NJ","23454","1234","958", "123-7367","J Associates");
1 row created.
SQL> insert into customer(cust_no,lastname,firstname,midinit,street,city,state,zip,zip_4,area_code,phone,company_name)
  2                values(12,"Taker","Lawrence","T","1 Sask Rd.","Camp","NJ","19191","3298","928", "123-7384","K Company");
1 row created.
SQL> insert into customer(cust_no,lastname,firstname,midinit,street,city,state,zip,zip_4,area_code,phone,company_name)
  2                values(13,"Richer","Doris","R","213 Easy Street","WarPease","RI","34343","2112","501", "123-7384","L Inc");
1 row created.
SQL> insert into customer( cust_no,lastname,firstname,midinit,street,city,state,zip,zip_4,area_code,phone,company_name)
  2                values(14,"Pete","Doris","P","9 Ave","New York","NY","45454","4222","112", "123-1234","M Company");
1 row created.
SQL>
SQL> create table ord(
  2           order_no               integer          primary key
  3          ,cust_no                integer
  4          ,order_date             date not null
  5          ,total_order_price      number(7,2)
  6          ,deliver_date           date
  7          ,deliver_time           varchar2(7)
  8          ,payment_method         varchar2(2)
  9          ,emp_no                 number(3,0)
 10          ,deliver_name           varchar2(35)
 11          ,gift_message           varchar2(100)
 12  );
Table created.
SQL>
SQL>
SQL> insert into ord(order_no,cust_no,order_date,total_order_price,deliver_date,deliver_time,payment_method,emp_no,deliver_name,gift_message)
  2           values(1,1,"14-Feb-2002", 23.00, "14-Feb-2002", "12 noon", "CA",1, null, "Gift for wife");
1 row created.
SQL> insert into ord(order_no  ,cust_no ,order_date ,total_order_price ,deliver_date ,deliver_time ,payment_method ,emp_no,deliver_name ,gift_message )
  2           values(2,1,"14-Feb-2003", 510.98, "14-feb-2003", "5 pm", "NY",7, "Rose Ted", "Happy Valentines Day to Mother");
1 row created.
SQL> insert into ord(order_no  ,cust_no ,order_date ,total_order_price ,deliver_date ,deliver_time,payment_method ,emp_no,deliver_name ,gift_message )
  2           values(3, 2,"14-Feb-2004", 315.99, "14-feb-2004", "3 pm", "VS",2, "Ani Forest", "Happy Valentines Day to Father");
1 row created.
SQL> insert into ord(order_no  ,cust_no ,order_date ,total_order_price ,deliver_date ,deliver_time,payment_method ,emp_no,deliver_name ,gift_message )
  2           values(4, 2,"14-Feb-1999", 191.95, "14-feb-1999", "2 pm", "NJ",2, "O. John", "Happy Valentines Day");
1 row created.
SQL> insert into ord(order_no  ,cust_no ,order_date ,total_order_price ,deliver_date ,deliver_time,payment_method ,emp_no,deliver_name ,gift_message    )
  2           values(5, 6,"4-mar-2002", 101.95, "5-mar-2002", "2:30 pm", "MO"   , 2, "Cora", "Happy Birthday from John");
1 row created.
SQL> insert into ord(order_no  ,cust_no ,order_date ,total_order_price ,deliver_date ,deliver_time,payment_method ,emp_no,deliver_name ,gift_message )
  2           values(6, 9,"7-apr-2003", 221.95, "7-apr-2003", "3 pm", "MA", 2, "Sake Keith", "Happy Birthday from Joe" );
1 row created.
SQL> insert into ord(order_no  ,cust_no ,order_date ,total_order_price ,deliver_date ,deliver_time,payment_method ,emp_no,deliver_name ,gift_message )
  2           values(7, 9,"20-jun-2004", 315.95, "21-jun-2004", "12 noon", "BC", 2, "Jessica Li", "Happy Birthday from Jessica");
1 row created.
SQL> insert into ord(order_no  ,cust_no ,order_date ,total_order_price ,deliver_date ,deliver_time,payment_method ,emp_no,deliver_name ,gift_message )
  2           values (8, 12, "31-dec-1999", 135.95, "1-jan-2000", "12 noon", "DI",      3, "Larry", "Happy New Year from Lawrence");
1 row created.
SQL> insert into ord(order_no  ,cust_no ,order_date ,total_order_price ,deliver_date ,deliver_time,payment_method ,emp_no,deliver_name ,gift_message )
  2           values (9, 12, "26-dec-2003", 715.95, "2-jan-2004", "12 noon", "SK",7, "Did", "Happy Birthday from Nancy" );
1 row created.
SQL> insert into ord(order_no  ,cust_no ,order_date ,total_order_price ,deliver_date ,deliver_time,payment_method ,emp_no,deliver_name ,gift_message )
  2           values(10, 4, sysdate-1, 119.95, sysdate+2, "6:30 pm", "VG",2, "P. Jing", "Happy Valentines Day to Jason");
1 row created.
SQL> insert into ord(order_no  ,cust_no ,order_date ,total_order_price ,deliver_date ,deliver_time,payment_method ,emp_no,deliver_name ,gift_message )
  2           values(11, 2, sysdate, 310.00, sysdate+2, "3:30 pm", "DC",2, "C. Late", "Happy Birthday Day to Jack");
1 row created.
SQL> insert into ord(order_no  ,cust_no ,order_date ,total_order_price ,deliver_date ,deliver_time,payment_method ,emp_no,deliver_name ,gift_message)
  2           values(12, 7, sysdate-3, 121.95, sysdate-2, "1:30 pm", "AC",2, "W. Last", "Happy Birthday Day to You");
1 row created.
SQL> insert into ord(order_no  ,cust_no ,order_date ,total_order_price ,deliver_date ,deliver_time,payment_method ,emp_no,deliver_name ,gift_message)
  2           values(13, 7, sysdate, 211.95, sysdate-4, "4:30 pm", "CA",2, "J. Bond", "Thanks for hard working");
1 row created.
SQL>
SQL>
SQL>
SQL> SELECT cust_no, lastname
  2    FROM customer c
  3    WHERE NOT EXISTS
  4    (SELECT cust_no FROM ord
  5     WHERE cust_no = c.cust_no);
   CUST_NO LASTNAME
---------- --------------------
         5 Hill
         8 Chili
         3 Jason
        10 Hack
        14 Pete
        13 Richer
        11 Bill
7 rows selected.
SQL>
SQL> drop table customer;
Table dropped.
SQL>
SQL> set autotrace off
SQL>
SQL> drop table ord;
Table dropped.
SQL>
SQL>
SQL> --



The EXISTS condition can also be combined with the NOT operator

SQL> CREATE TABLE EMP (EMPNO NUMBER(4) NOT NULL,
  2                    ENAME VARCHAR2(10),
  3                    JOB VARCHAR2(9),
  4                    MGR NUMBER(4),
  5                    HIREDATE DATE,
  6                    SAL NUMBER(7, 2),
  7                    COMM NUMBER(7, 2),
  8                    DEPTNO NUMBER(2));
SQL>
SQL> INSERT INTO EMP VALUES (7369, "SMITH", "CLERK",    7902, TO_DATE("17-DEC-1980", "DD-MON-YYYY"), 800, NULL, 20);
SQL> INSERT INTO EMP VALUES (7499, "ALLEN", "SALESMAN", 7698, TO_DATE("20-FEB-1981", "DD-MON-YYYY"), 1600, 300, 30);
SQL> INSERT INTO EMP VALUES (7521, "WARD",  "SALESMAN", 7698, TO_DATE("22-FEB-1981", "DD-MON-YYYY"), 1250, 500, 30);
SQL> INSERT INTO EMP VALUES (7566, "JONES", "MANAGER",  7839, TO_DATE("2-APR-1981",  "DD-MON-YYYY"), 2975, NULL, 20);
SQL> INSERT INTO EMP VALUES (7654, "MARTIN", "SALESMAN", 7698,TO_DATE("28-SEP-1981", "DD-MON-YYYY"), 1250, 1400, 30);
SQL> INSERT INTO EMP VALUES (7698, "BLAKE", "MANAGER", 7839,TO_DATE("1-MAY-1981", "DD-MON-YYYY"), 2850, NULL, 30);
SQL> INSERT INTO EMP VALUES (7782, "CLARK", "MANAGER", 7839,TO_DATE("9-JUN-1981", "DD-MON-YYYY"), 2450, NULL, 10);
SQL> INSERT INTO EMP VALUES (7788, "SCOTT", "ANALYST", 7566,TO_DATE("09-DEC-1982", "DD-MON-YYYY"), 3000, NULL, 20);
SQL> INSERT INTO EMP VALUES (7839, "KING", "PRESIDENT", NULL,TO_DATE("17-NOV-1981", "DD-MON-YYYY"), 5000, NULL, 10);
SQL> INSERT INTO EMP VALUES (7844, "TURNER", "SALESMAN", 7698,TO_DATE("8-SEP-1981", "DD-MON-YYYY"), 1500, 0, 30);
SQL> INSERT INTO EMP VALUES (7876, "ADAMS", "CLERK", 7788,TO_DATE("12-JAN-1983", "DD-MON-YYYY"), 1100, NULL, 20);
SQL> INSERT INTO EMP VALUES (7900, "JAMES", "CLERK", 7698,TO_DATE("3-DEC-1981", "DD-MON-YYYY"), 950, NULL, 30);
SQL> INSERT INTO EMP VALUES (7902, "FORD", "ANALYST", 7566,TO_DATE("3-DEC-1981", "DD-MON-YYYY"), 3000, NULL, 20);
SQL> INSERT INTO EMP VALUES (7934, "MILLER", "CLERK", 7782,TO_DATE("23-JAN-1982", "DD-MON-YYYY"), 1300, NULL, 10);
SQL>
SQL> CREATE TABLE DEPT (DEPTNO NUMBER(2),DNAME VARCHAR2(14),LOC VARCHAR2(13) );
SQL>
SQL> INSERT INTO DEPT VALUES (10, "ACCOUNTING", "NEW YORK");
SQL> INSERT INTO DEPT VALUES (20, "RESEARCH", "DALLAS");
SQL> INSERT INTO DEPT VALUES (30, "SALES", "CHICAGO");
SQL> INSERT INTO DEPT VALUES (40, "OPERATIONS", "BOSTON");
SQL>
SQL>
SQL> select * from emp;
     EMPNO ENAME      JOB              MGR HIREDATE         SAL       COMM     DEPTNO
---------- ---------- --------- ---------- --------- ---------- ---------- ----------
      7369 SMITH      CLERK           7902 17-DEC-80        800                    20
      7499 ALLEN      SALESMAN        7698 20-FEB-81       1600        300         30
      7521 WARD       SALESMAN        7698 22-FEB-81       1250        500         30
      7566 JONES      MANAGER         7839 02-APR-81       2975                    20
      7654 MARTIN     SALESMAN        7698 28-SEP-81       1250       1400         30
      7698 BLAKE      MANAGER         7839 01-MAY-81       2850                    30
      7782 CLARK      MANAGER         7839 09-JUN-81       2450                    10
      7788 SCOTT      ANALYST         7566 09-DEC-82       3000                    20
      7839 KING       PRESIDENT            17-NOV-81       5000                    10
      7844 TURNER     SALESMAN        7698 08-SEP-81       1500          0         30
      7876 ADAMS      CLERK           7788 12-JAN-83       1100                    20
     EMPNO ENAME      JOB              MGR HIREDATE         SAL       COMM     DEPTNO
---------- ---------- --------- ---------- --------- ---------- ---------- ----------
      7900 JAMES      CLERK           7698 03-DEC-81        950                    30
      7902 FORD       ANALYST         7566 03-DEC-81       3000                    20
      7934 MILLER     CLERK           7782 23-JAN-82       1300                    10
SQL>
SQL> select * from dept;
    DEPTNO DNAME          LOC
---------- -------------- -------------
        10 ACCOUNTING     NEW YORK
        20 RESEARCH       DALLAS
        30 SALES          CHICAGO
        40 OPERATIONS     BOSTON
SQL>
SQL> -- NOT EXISTS
SQL>
SQL> -- The EXISTS condition can also be combined with the NOT operator.
SQL>
SQL>     SELECT *
  2      FROM emp
  3      WHERE not exists (select * from dept Where dept.deptno = emp.deptno);
SQL>
SQL>
SQL>
SQL> drop table dept;
SQL> drop table emp;



Use EXISTS to link two queries

SQL> CREATE TABLE EMP (EMPNO NUMBER(4) NOT NULL,
  2                    ENAME VARCHAR2(10),
  3                    JOB VARCHAR2(9),
  4                    MGR NUMBER(4),
  5                    HIREDATE DATE,
  6                    SAL NUMBER(7, 2),
  7                    COMM NUMBER(7, 2),
  8                    DEPTNO NUMBER(2));
SQL>
SQL> INSERT INTO EMP VALUES (7369, "SMITH", "CLERK",    7902, TO_DATE("17-DEC-1980", "DD-MON-YYYY"), 800, NULL, 20);
SQL> INSERT INTO EMP VALUES (7499, "ALLEN", "SALESMAN", 7698, TO_DATE("20-FEB-1981", "DD-MON-YYYY"), 1600, 300, 30);
SQL> INSERT INTO EMP VALUES (7521, "WARD",  "SALESMAN", 7698, TO_DATE("22-FEB-1981", "DD-MON-YYYY"), 1250, 500, 30);
SQL> INSERT INTO EMP VALUES (7566, "JONES", "MANAGER",  7839, TO_DATE("2-APR-1981",  "DD-MON-YYYY"), 2975, NULL, 20);
SQL> INSERT INTO EMP VALUES (7654, "MARTIN", "SALESMAN", 7698,TO_DATE("28-SEP-1981", "DD-MON-YYYY"), 1250, 1400, 30);
SQL> INSERT INTO EMP VALUES (7698, "BLAKE", "MANAGER", 7839,TO_DATE("1-MAY-1981", "DD-MON-YYYY"), 2850, NULL, 30);
SQL> INSERT INTO EMP VALUES (7782, "CLARK", "MANAGER", 7839,TO_DATE("9-JUN-1981", "DD-MON-YYYY"), 2450, NULL, 10);
SQL> INSERT INTO EMP VALUES (7788, "SCOTT", "ANALYST", 7566,TO_DATE("09-DEC-1982", "DD-MON-YYYY"), 3000, NULL, 20);
SQL> INSERT INTO EMP VALUES (7839, "KING", "PRESIDENT", NULL,TO_DATE("17-NOV-1981", "DD-MON-YYYY"), 5000, NULL, 10);
SQL> INSERT INTO EMP VALUES (7844, "TURNER", "SALESMAN", 7698,TO_DATE("8-SEP-1981", "DD-MON-YYYY"), 1500, 0, 30);
SQL> INSERT INTO EMP VALUES (7876, "ADAMS", "CLERK", 7788,TO_DATE("12-JAN-1983", "DD-MON-YYYY"), 1100, NULL, 20);
SQL> INSERT INTO EMP VALUES (7900, "JAMES", "CLERK", 7698,TO_DATE("3-DEC-1981", "DD-MON-YYYY"), 950, NULL, 30);
SQL> INSERT INTO EMP VALUES (7902, "FORD", "ANALYST", 7566,TO_DATE("3-DEC-1981", "DD-MON-YYYY"), 3000, NULL, 20);
SQL> INSERT INTO EMP VALUES (7934, "MILLER", "CLERK", 7782,TO_DATE("23-JAN-1982", "DD-MON-YYYY"), 1300, NULL, 10);
SQL>
SQL> CREATE TABLE DEPT (DEPTNO NUMBER(2),DNAME VARCHAR2(14),LOC VARCHAR2(13) );
SQL>
SQL> INSERT INTO DEPT VALUES (10, "ACCOUNTING", "NEW YORK");
SQL> INSERT INTO DEPT VALUES (20, "RESEARCH", "DALLAS");
SQL> INSERT INTO DEPT VALUES (30, "SALES", "CHICAGO");
SQL> INSERT INTO DEPT VALUES (40, "OPERATIONS", "BOSTON");
SQL>
SQL> select * from emp;
     EMPNO ENAME      JOB              MGR HIREDATE         SAL       COMM     DEPTNO
---------- ---------- --------- ---------- --------- ---------- ---------- ----------
      7369 SMITH      CLERK           7902 17-DEC-80        800                    20
      7499 ALLEN      SALESMAN        7698 20-FEB-81       1600        300         30
      7521 WARD       SALESMAN        7698 22-FEB-81       1250        500         30
      7566 JONES      MANAGER         7839 02-APR-81       2975                    20
      7654 MARTIN     SALESMAN        7698 28-SEP-81       1250       1400         30
      7698 BLAKE      MANAGER         7839 01-MAY-81       2850                    30
      7782 CLARK      MANAGER         7839 09-JUN-81       2450                    10
      7788 SCOTT      ANALYST         7566 09-DEC-82       3000                    20
      7839 KING       PRESIDENT            17-NOV-81       5000                    10
      7844 TURNER     SALESMAN        7698 08-SEP-81       1500          0         30
      7876 ADAMS      CLERK           7788 12-JAN-83       1100                    20
     EMPNO ENAME      JOB              MGR HIREDATE         SAL       COMM     DEPTNO
---------- ---------- --------- ---------- --------- ---------- ---------- ----------
      7900 JAMES      CLERK           7698 03-DEC-81        950                    30
      7902 FORD       ANALYST         7566 03-DEC-81       3000                    20
      7934 MILLER     CLERK           7782 23-JAN-82       1300                    10
SQL>
SQL> select * from dept;
    DEPTNO DNAME          LOC
---------- -------------- -------------
        10 ACCOUNTING     NEW YORK
        20 RESEARCH       DALLAS
        30 SALES          CHICAGO
        40 OPERATIONS     BOSTON
SQL>
SQL>
SQL>
SQL> SELECT * FROM emp WHERE EXISTS
  2  (select * from dept where dept.deptno = emp.deptno);
     EMPNO ENAME      JOB              MGR HIREDATE         SAL       COMM     DEPTNO
---------- ---------- --------- ---------- --------- ---------- ---------- ----------
      7934 MILLER     CLERK           7782 23-JAN-82       1300                    10
      7839 KING       PRESIDENT            17-NOV-81       5000                    10
      7782 CLARK      MANAGER         7839 09-JUN-81       2450                    10
      7902 FORD       ANALYST         7566 03-DEC-81       3000                    20
      7876 ADAMS      CLERK           7788 12-JAN-83       1100                    20
      7788 SCOTT      ANALYST         7566 09-DEC-82       3000                    20
      7566 JONES      MANAGER         7839 02-APR-81       2975                    20
      7369 SMITH      CLERK           7902 17-DEC-80        800                    20
      7900 JAMES      CLERK           7698 03-DEC-81        950                    30
      7844 TURNER     SALESMAN        7698 08-SEP-81       1500          0         30
      7698 BLAKE      MANAGER         7839 01-MAY-81       2850                    30
     EMPNO ENAME      JOB              MGR HIREDATE         SAL       COMM     DEPTNO
---------- ---------- --------- ---------- --------- ---------- ---------- ----------
      7654 MARTIN     SALESMAN        7698 28-SEP-81       1250       1400         30
      7521 WARD       SALESMAN        7698 22-FEB-81       1250        500         30
      7499 ALLEN      SALESMAN        7698 20-FEB-81       1600        300         30
SQL>
SQL>
SQL>
SQL> drop table dept;
SQL> drop table emp;