2VVG_
Вы заблуждаетесь, на средних и больщих объемах данных (миллион, скажем), Ваш
вариант намного более долгий. Сам на этом попался.
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
32.
33.
34.
35.
36.
37.
38.
39.
40.
41.
SET NOCOUNT ON
GO
CREATE DATABASE DB1
GO
USE DB1
GO
CREATE TABLE T1 (id int identity primary key, v1 varchar( 100 ))
CREATE TABLE T2 (id int identity primary key, v1 varchar( 100 ))
GO
declare @i int
set @i = 1
while @i < 1000000
begin
INSERT T1 VALUES (CAST(@i as varchar))
set @i = @i + 1
end
GO
declare @i int
set @i = 500000
while @i < 1000000
begin
INSERT T2 VALUES (CAST(@i as varchar))
set @i = @i + 1
end
'Table 'T1'. Scan count 2, logical reads 5660, physical reads 0, read-ahead reads 0.
'Table 'T2'. Scan count 2 , logical reads 2846 , physical reads 0 , read-ahead reads 0 .
'SQL Server Execution Times:
CPU time = 3719 ms, elapsed time = 8867 ms.
select * from T1
left outer join T2 on T1.id=T2.id
where T2.id is null
'Table 'T1'. Scan count 1 , logical reads 2830 , physical reads 0 , read-ahead reads 0 .
'Table 'T2'. Scan count 1, logical reads 1423, physical reads 0, read-ahead reads 0.
'SQL Server Execution Times:
CPU time = 2578 ms, elapsed time = 6472 ms.
SELECT * FROM T1
WHERE id NOT IN (SELECT id FROM T2)
2MiCe:
Что-то не то... Все выводит.
