Create index based on two columns
18>
19> CREATE TABLE works_on (emp_no INTEGER NOT NULL,
20> project_no CHAR(4) NOT NULL,
21> job CHAR (15) NULL,
22> enter_date DATETIME NULL)
23>
24> insert into works_on values (1, 'p1', 'analyst', '1997.10.1')
25> insert into works_on values (1, 'p3', 'manager', '1999.1.1')
26> insert into works_on values (2, 'p2', 'clerk', '1998.2.15')
27> insert into works_on values (2, 'p2', NULL, '1998.6.1')
28> insert into works_on values (3, 'p2', NULL, '1997.12.15')
29> insert into works_on values (4, 'p3', 'analyst', '1998.10.15')
30> insert into works_on values (5, 'p1', 'manager', '1998.4.15')
31> insert into works_on values (6, 'p1', NULL, '1998.8.1')
32> insert into works_on values (7, 'p2', 'clerk', '1999.2.1')
33> insert into works_on values (8, 'p3', 'clerk', '1997.11.15')
34> insert into works_on values (7, 'p1', 'clerk', '1998.1.4')
35>
36> select * from works_on
37> GO
(1 rows affected)
(1 rows affected)
(1 rows affected)
(1 rows affected)
(1 rows affected)
(1 rows affected)
(1 rows affected)
(1 rows affected)
(1 rows affected)
(1 rows affected)
(1 rows affected)
emp_no project_no job enter_date
----------- ---------- --------------- -----------------------
1 p1 analyst 1997-10-01 00:00:00.000
1 p3 manager 1999-01-01 00:00:00.000
2 p2 clerk 1998-02-15 00:00:00.000
2 p2 NULL 1998-06-01 00:00:00.000
3 p2 NULL 1997-12-15 00:00:00.000
4 p3 analyst 1998-10-15 00:00:00.000
5 p1 manager 1998-04-15 00:00:00.000
6 p1 NULL 1998-08-01 00:00:00.000
7 p2 clerk 1999-02-01 00:00:00.000
8 p3 clerk 1997-11-15 00:00:00.000
7 p1 clerk 1998-01-04 00:00:00.000
(11 rows affected)
1>
2>
3> -- AND Operator
4>
5> CREATE INDEX i_works ON works_on(emp_no, enter_date)
6> GO
1>
2> SELECT * FROM works_on WHERE emp_no = 8 AND enter_date='11.15.1997'
3> GO
emp_no project_no job enter_date
----------- ---------- --------------- -----------------------
8 p3 clerk 1997-11-15 00:00:00.000
(1 rows affected)
1>
2> drop table works_on
3> GO
1>
2>
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