SQL Server/T-SQL/System/SHOWPLAN TEXT — различия между версиями

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м (1 версия)
 
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Текущая версия на 10:20, 26 мая 2010

SET SHOWPLAN_TEXT ON

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>



SET SHOWPLAN_TEXT ON for an index

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>