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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));
Table created.
SQL>
SQL> INSERT INTO EMP VALUES (7369, 'SMITH', 'CLERK', 7902, TO_DATE('17-DEC-1980', 'DD-MON-YYYY'), 800, NULL, 20);
1 row created.
SQL> INSERT INTO EMP VALUES (7499, 'ALLEN', 'SALESMAN', 7698, TO_DATE('20-FEB-1981', 'DD-MON-YYYY'), 1600, 300, 30);
1 row created.
SQL> INSERT INTO EMP VALUES (7521, 'WARD', 'SALESMAN', 7698, TO_DATE('22-FEB-1981', 'DD-MON-YYYY'), 1250, 500, 30);
1 row created.
SQL> INSERT INTO EMP VALUES (7566, 'JONES', 'MANAGER', 7839, TO_DATE('2-APR-1981', 'DD-MON-YYYY'), 2975, NULL, 20);
1 row created.
SQL> INSERT INTO EMP VALUES (7654, 'MARTIN', 'SALESMAN', 7698,TO_DATE('28-SEP-1981', 'DD-MON-YYYY'), 1250, 1400, 30);
1 row created.
SQL> INSERT INTO EMP VALUES (7698, 'BLAKE', 'MANAGER', 7839,TO_DATE('1-MAY-1981', 'DD-MON-YYYY'), 2850, NULL, 30);
1 row created.
SQL> INSERT INTO EMP VALUES (7782, 'CLARK', 'MANAGER', 7839,TO_DATE('9-JUN-1981', 'DD-MON-YYYY'), 2450, NULL, 10);
1 row created.
SQL> INSERT INTO EMP VALUES (7788, 'SCOTT', 'ANALYST', 7566,TO_DATE('09-DEC-1982', 'DD-MON-YYYY'), 3000, NULL, 20);
1 row created.
SQL> INSERT INTO EMP VALUES (7839, 'KING', 'PRESIDENT', NULL,TO_DATE('17-NOV-1981', 'DD-MON-YYYY'), 5000, NULL, 10);
1 row created.
SQL> INSERT INTO EMP VALUES (7844, 'TURNER', 'SALESMAN', 7698,TO_DATE('8-SEP-1981', 'DD-MON-YYYY'), 1500, 0, 30);
1 row created.
SQL> INSERT INTO EMP VALUES (7876, 'ADAMS', 'CLERK', 7788,TO_DATE('12-JAN-1983', 'DD-MON-YYYY'), 1100, NULL, 20);
1 row created.
SQL> INSERT INTO EMP VALUES (7900, 'JAMES', 'CLERK', 7698,TO_DATE('3-DEC-1981', 'DD-MON-YYYY'), 950, NULL, 30);
1 row created.
SQL> INSERT INTO EMP VALUES (7902, 'FORD', 'ANALYST', 7566,TO_DATE('3-DEC-1981', 'DD-MON-YYYY'), 3000, NULL, 20);
1 row created.
SQL> INSERT INTO EMP VALUES (7934, 'MILLER', 'CLERK', 7782,TO_DATE('23-JAN-1982', 'DD-MON-YYYY'), 1300, NULL, 10);
1 row created.
SQL>
SQL> select * from emp;
EMPNO ENAME JOB MGR HIREDATE SAL COMM DEPTNO
---------- ---------- --------- ---------- ----------- ---------- ---------- ----------
7369 SMITH CLERK 7902 1980-DEC-17 800 20
7499 ALLEN SALESMAN 7698 1981-FEB-20 1600 300 30
7521 WARD SALESMAN 7698 1981-FEB-22 1250 500 30
7566 JONES MANAGER 7839 1981-APR-02 2975 20
7654 MARTIN SALESMAN 7698 1981-SEP-28 1250 1400 30
7698 BLAKE MANAGER 7839 1981-MAY-01 2850 30
7782 CLARK MANAGER 7839 1981-JUN-09 2450 10
7788 SCOTT ANALYST 7566 1982-DEC-09 3000 20
7839 KING PRESIDENT 1981-NOV-17 5000 10
7844 TURNER SALESMAN 7698 1981-SEP-08 1500 0 30
7876 ADAMS CLERK 7788 1983-JAN-12 1100 20
7900 JAMES CLERK 7698 1981-DEC-03 950 30
7902 FORD ANALYST 7566 1981-DEC-03 3000 20
7934 MILLER CLERK 7782 1982-JAN-23 1300 10
14 rows selected.
SQL>
SQL> --Writing Correlated Subqueries
SQL>
SQL> --A correlated subquery references one or more columns in the outer query.
SQL> --The subquery is known as a correlated subquery because the subquery is related to the outer query.
SQL>
SQL> SELECT empno, mgr,ename, sal
2 FROM emp outer
3 WHERE sal >
4 (SELECT AVG(sal)
5 FROM emp inner
6 WHERE inner.empno = outer.mgr);
EMPNO MGR ENAME SAL
---------- ---------- ---------- ----------
7788 7566 SCOTT 3000
7902 7566 FORD 3000
SQL>
SQL>
SQL> drop table emp;
Table dropped.
SQL>
SQL>
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