в 13:46, 26 мая 2010

2010-05-26T13:46:06Z

Admin: 1 версия

2010-05-26T10:20:36Z

1 версия

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==SET SHOWPLAN_TEXT ON==



<source lang="sql">

19>
20> CREATE TABLE works_on (emp_no INTEGER NOT NULL,
21> project_no CHAR(4) NOT NULL,
22> job CHAR (15) NULL,
23> enter_date DATETIME NULL)
24>
25> insert into works_on values (1, "p1", "analyst", "1997.10.1")
26> insert into works_on values (1, "p3", "manager", "1999.1.1")
27> insert into works_on values (2, "p2", "clerk", "1998.2.15")
28> insert into works_on values (2, "p2", NULL, "1998.6.1")
29> insert into works_on values (3, "p2", NULL, "1997.12.15")
30> insert into works_on values (4, "p3", "analyst", "1998.10.15")
31> insert into works_on values (5, "p1", "manager", "1998.4.15")
32> insert into works_on values (6, "p1", NULL, "1998.8.1")
33> insert into works_on values (7, "p2", "clerk", "1999.2.1")
34> insert into works_on values (8, "p3", "clerk", "1997.11.15")
35> insert into works_on values (7, "p1", "clerk", "1998.1.4")
36>
37> select * from works_on
38> GO
Msg 2714, Level 16, State 6, Server sqle\SQLEXPRESS, Line 20
There is already an object named "works_on" in the database.
1> CREATE TABLE employee (emp_no INTEGER NOT NULL,
2> emp_fname CHAR(20) NOT NULL,
3> emp_lname CHAR(20) NOT NULL,
4> dept_no CHAR(4) NULL)
5>
6> insert into employee values(1, "Matthew", "Smith", "d3")
7> insert into employee values(2, "Ann", "Jones", "d3")
8> insert into employee values(3, "John", "Barrimore","d1")
9> insert into employee values(4, "James", "James", "d2")
10> insert into employee values(5, "Elsa", "Bertoni", "d2")
11> insert into employee values(6, "Elke", "Hansel", "d2")
12> insert into employee values(7, "Sybill", "Moser", "d1")
13>
14> select * from employee
15> GO
Msg 2714, Level 16, State 6, Server sqle\SQLEXPRESS, Line 1
There is already an object named "employee" in the database.
1>
2> --The FORCE ORDER hint forces the optimizer to join tables in the order in which
3> --they are specified in a query
4>
5> SET SHOWPLAN_TEXT ON
6> GO
1> select emp_lname, emp_fname
2> from works_on JOIN employee
3> ON employee.emp_no = works_on.emp_no
4> WHERE works_on.job = "Analyst"
5> option (force order)
6> GO
StmtText
------------------------------------------------------------------------------------------------------------------------
---------------------------
select emp_lname, emp_fname
from works_on JOIN employee
ON employee.emp_no = works_on.emp_no
WHERE works_on.job = "Analyst"
option (force order)
(1 rows affected)
StmtText
------------------------------------------------------------------------------------------------------------
|--Hash Match(Inner Join, HASH:([master].[dbo].[works_on].[emp_no])=([master].[dbo].[employee].[emp_no]))
|--Table Scan(OBJECT:([master].[dbo].[works_on]), WHERE:([master].[dbo].[works_on].[job]="Analyst"))
|--Table Scan(OBJECT:([master].[dbo].[employee]))
(3 rows affected)
1> SET SHOWPLAN_TEXT OFF
2> GO
1> drop table employee
2> drop table works_on
3> GO
1>
2>

</source>

==SET SHOWPLAN_TEXT ON for an index==



<source lang="sql">

23> CREATE TABLE works_on (emp_no INTEGER NOT NULL,
24> project_no CHAR(4) NOT NULL,
25> job CHAR (15) NULL,
26> enter_date DATETIME NULL)
27>
28> insert into works_on values (1, "p1", "analyst", "1997.10.1")
29> insert into works_on values (1, "p3", "manager", "1999.1.1")
30> insert into works_on values (2, "p2", "clerk", "1998.2.15")
31> insert into works_on values (2, "p2", NULL, "1998.6.1")
32> insert into works_on values (3, "p2", NULL, "1997.12.15")
33> insert into works_on values (4, "p3", "analyst", "1998.10.15")
34> insert into works_on values (5, "p1", "manager", "1998.4.15")
35> insert into works_on values (6, "p1", NULL, "1998.8.1")
36> insert into works_on values (7, "p2", "clerk", "1999.2.1")
37> insert into works_on values (8, "p3", "clerk", "1997.11.15")
38> insert into works_on values (7, "p1", "clerk", "1998.1.4")
39>
40> select * from works_on
41> 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>
3>
4> SET SHOWPLAN_TEXT ON
5> GO
1>
2> select * from works_on WITH (index(0))
3> where emp_no = 10102
4> GO
StmtText
------------------------------------------------------------------------
select * from works_on WITH (index(0))
where emp_no = 10102
(1 rows affected)
StmtText
--------------------------------------------------------------------------------------------------------
|--Table Scan(OBJECT:([master].[dbo].[works_on]), WHERE:([master].[dbo].[works_on].[emp_no]=(10102)))
(1 rows affected)
1>
2> SET SHOWPLAN_TEXT OFF
3> GO
1> drop table works_on
2> GO
1>

</source>

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в 13:46, 26 мая 2010

Admin: 1 версия