Optimize Left join query

[marsss]

Hello, I would like to get some help to optimize a query. Problem is mostly due to slow speed it go. Since it s put into a view, i dont want to put a where clause for the "datetime" and lets the user put it when he call my view. But without this where clause, my query run real slow. With the same where clause such "where datetime > getdate() -1" if it s put at first in my view, it run like 2-3x faster than if i specify it when i call my view.

Here is what I have :
Table

key		datetime	kind	value
1		2006-05-30	1		a
1		2006-05-29	2		b
1		2006-05-28	2		c
1		2006-05-27	2		d
1		2006-05-24	3		b
1		2006-05-23	3		c
1		2006-05-22	3		d
2		2006-05-28	1		a
2		2006-05-29	2		b
2		2006-05-28	2		c
2		2006-05-27	2		d
2		2006-05-24	3		b
2		2006-05-23	3		c
2		2006-05-22	3		d
3		2006-05-23	1		a
3		2006-05-29	2		b
3		2006-05-28	2		c
3		2006-05-27	2		d
3		2006-05-24	3		b
3		2006-05-23	3		c
3		2006-05-22	3		d

Here is what i want :

key		datetime	date2		value2	date3		value3
1		2006-05-30  2006-05-29	b		2006-05-24	b
2		2006-05-28  2006-05-27	d		2006-05-24	b
3		2006-05-23	NULL		NULL	2006-05-22	d

It s like turn my table from vertical to horizontal, and match some record. Like for a specific date with kind = 1, i want the lastess event before that date of kind 2 and 3 with their value

Here is the query i ended with (it s quite more long in my real one since i have like 7-8 diff date, but using the same template, making 7-8 Left join)

select block1.key, block1.date1 datetime, block2.date2, block2_value.value value2, block3.date3, block3_value.value value3
from
	(	(
			select table.key, table.datetime date1
			from realtable table
			where table.kind = 1
			--and table.datetime > 'XXXX-XX-XX'
		) block1
		left join
		(
			(
				select table.key, table.datetime date1, max(table2.datetime) date2
				from realtable  table, realtable  table2
				where table.datetime > table2.datetime, table.key = table2.key, table2.kind = 2
			) block2_date
			inner join
			realtable block2_value
			on block2_date.date2 = block2_value.datetime and block2_date.key = block2_value.key
				and block2_date.kind = block2_value.kind
		) block2
		on block1.key = block2_date.key and block1.date1 = block2.date1
	)
	left join
	(
		(
			select table.key, table.datetime date1, max(table3.datetime) date3
			from realtable  table, realtable  table3
			where table.datetime > table3.datetime, table.key = table3.key, table3.kind = 3
		) block3_date
		inner join
		realtable block3_value
		on block3_date.date3 = block3_value.datetime and block3_date.key = block3_value.key
				and block3_date.kind = block3_value.kind
	) block3
	on block1.key = block3.key and block1.date1 = block3.date1

is there any other way to make this better?