顯示出來了！


結論：
SQL Server在執行相關的操作的時候都會智能去判斷是否值得去做，比如在頁面數太小的情況下可以不去重建索引，rebuild reindex 。類似的，在SQL Server 2005 里面也多了許多智能的判斷來保證一個完整龐大而又不失智能的設計，
比如：
生成查詢計劃的閥值
緩存機制，緩存的篩選，LRU算法
預讀機制
checkpoint減少回滾距離
智能join判斷
重編譯

了解SQL Server這種類似的軟件產品能夠為我們在設計產品的時候提供更多的思路想法，即使你了解上面的東西對你的SQL開發也不會有太多幫助。

另外附上幾種方式的區別：
reindex是比較好的選擇，速度快，但是他不能在線操作
INDEXDEFRAG 比較慢，但是可以在線操作
rebuild建議在碎片較少時采用。

附上微軟的重建索引腳本，從里面也可以看出微軟根據碎片大小推薦的方式，不過這個要隨每個不同的數據庫而定。-- ensure a USE <databasename> statement has been executed first.
SET NOCOUNT ON;
DECLARE @objectid int;
DECLARE @indexid int;
DECLARE @partitioncount bigint;
DECLARE @schemaname sysname;
DECLARE @objectname sysname;
DECLARE @indexname sysname;
DECLARE @partitionnum bigint;
DECLARE @partitions bigint;
DECLARE @frag float;
DECLARE @command varchar(8000);
-- ensure the temporary table does not exist
IF EXISTS (SELECT name FROM sys.objects WHERE name = 'work_to_do')
 DROP TABLE work_to_do;
-- conditionally select from the function, converting object and index IDs to names.
SELECT
 object_id AS objectid,
 index_id AS indexid,
 partition_number AS partitionnum,
 avg_fragmentation_in_percent AS frag
INTO work_to_do
FROM sys.dm_db_index_physical_stats (DB_ID(), NULL, NULL , NULL, 'LIMITED')
WHERE avg_fragmentation_in_percent > 10.0 AND index_id > 0;
-- Declare the cursor for the list of partitions to be processed.
DECLARE partitions CURSOR FOR SELECT * FROM work_to_do;

-- Open the cursor.
OPEN partitions;

-- Loop through the partitions.
FETCH NEXT
 FROM partitions
 INTO @objectid, @indexid, @partitionnum, @frag;

WHILE @@FETCH_STATUS = 0
 BEGIN;
 SELECT @objectname = o.name, @schemaname = s.name
 FROM sys.objects AS o
 JOIN sys.schemas as s ON s.schema_id = o.schema_id
 WHERE o.object_id = @objectid;

 SELECT @indexname = name
 FROM sys.indexes
 WHERE object_id = @objectid AND index_id = @indexid;

 SELECT @partitioncount = count (*)
 FROM sys.partitions
 WHERE object_id = @objectid AND index_id = @indexid;

-- 30 is an arbitrary decision point at which to switch between reorganizing and rebuilding
IF @frag < 30.0
 BEGIN;
 SELECT @command = 'ALTER INDEX ' + @indexname + ' ON ' + @schemaname + '.' + @objectname + ' REORGANIZE';
 IF @partitioncount > 1
 SELECT @command = @command + ' PARTITION=' + CONVERT (CHAR, @partitionnum);
 EXEC (@command);
 END;

IF @frag >= 30.0
 BEGIN;
 SELECT @command = 'ALTER INDEX ' + @indexname +' ON ' + @schemaname + '.' + @objectname + ' REBUILD';
 IF @partitioncount > 1
 SELECT @command = @command + ' PARTITION=' + CONVERT (CHAR, @partitionnum);
 EXEC (@command);
 END;
PRINT 'Executed ' + @command;

FETCH NEXT FROM partitions INTO @objectid, @indexid, @partitionnum, @frag;
END;
-- Close and deallocate the cursor.
CLOSE partitions;
DEALLOCATE partitions;

-- drop the temporary table
IF EXISTS (SELECT name FROM sys.objects WHERE name = 'work_to_do')
 DROP TABLE work_to_do;
GO


BOL的推薦：
 

小于5沒必要重建，所以上面的SQL語句還是有得商量的地方。