原文发布时间为：2011-02-23 —— 来源于本人的百度文章 [由搬家工具导入]
reindex是比较好的选择，速度快，但是他不能在线操作
INDEXDEFRAG 比较慢，但是可以在线操作
rebuild建议在碎片较少时采用。
附上微软的重建索引脚本，从里面也可以看出微软根据碎片大小推荐的方式，不过这个要随每个不同的数据库而定。
-- 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>5 AND @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
如果提示 '(' 附近有语法错误，则将上面的 DB_ID() 这个改成当前库的ID （当前库的ID，你可以用查询分析器 SELECTDB_ID() 查询出来）
BOL的推荐：
> 5% 且 < = 30%
ALTER INDEX REORGANIZE
> 30%
ALTER INDEX REBUILD WITH (ONLINE = ON)*