求如下一代SQL语句。

有如下表：
ID                            content 
1    </v:shape><v:shape id="_x0000_s2100" type="#_x0000_t75" alt=""
2    href="http://www.xxx.com/xxx/=2596014"
3    target="_blank" style='position:absolute;margin-left:0;margin-top:4656pt;
4    width:12pt;height:12pt;z-index:1076' o:button="t">
5    <v:imagedata src="image005.gif" o:title="pdf"/>
6    <x:ClientData ObjectType="Pict">
7    <x:SizeWithCells/>
8    <x:CF>Bitmap</x:CF>
9    <x:AutoPict/>
10   </x:ClientData>
11   </v:shape><v:shape id="_x0000_s2106" type="#_x0000_t75" alt=""
12   href="http://www.xxx.com/xxx/=2596010"
13   target="_blank" style='position:absolute;margin-left:0;margin-top:65in;
14   width:12pt;height:12pt;z-index:1082' o:button="t">
15   <v:imagedata src="image005.gif" o:title="doc"/>
16   <x:ClientData ObjectType="Pdf">
17   <x:SizeWithCells/>
18   <x:CF>Bitmap</x:CF>
19   <x:AutoPict/>
20   </x:ClientData>
21   href="http://www.xxx.com/xxx/=2592292"
22   target="_blank"><area shape=Rect
23   coords="0, 22032, 16, 22048"
24   </v:shape><v:shape id="_x0000_s2109" type="#_x0000_t75" alt=""
25   href="http://www.xxx.com/xxx/=2596000"
26   target="_blank" style='position:absolute;margin-left:0;margin-top:4692pt;
27   width:12pt;height:12pt;z-index:1085' o:button="t">
28   <v:imagedata src="image008.gif" o:title="file"/>
29   <x:ClientData ObjectType="Doc">
30   <x:SizeWithCells/>
31   <x:CF>Bitmap</x:CF>
32   <x:AutoPict/>
33   </x:ClientData>
34   href="http://www.xxx.com/xxx/=2592296"
35   target="_blank"><area shape=Rect
36   coords="0, 22016, 16, 22032"
37   </v:shape><v:shape id="_x0000_s2103" type="#_x0000_t75" alt=""
38   href="http://www.xxx.com/xxx/=2596012"
39   target="_blank" style='position:absolute;margin-left:0;margin-top:4668pt;
40   width:12pt;height:12pt;z-index:1079' o:button="t">
41   <v:imagedata src="image005.gif" o:title="pdf"/>
42   <x:ClientData ObjectType="Pict">
43   <x:SizeWithCells/>
44   <x:CF>Bitmap</x:CF>
45   <x:AutoPict/>
46   </x:ClientData>
47   href="http://www.xxx.com/xxx/=2592298"
48   target="_blank"><area shape=Rect
49   coords="0, 22000, 16, 22016"
........表中的数据有上万条，我想实现这样的目的，context字段中内容有如下四种情况<x:ClientData ObjectType="Pict">;  <x:ClientData ObjectType="Pdf">;  <x:ClientData ObjectType="Doc">;  <x:ClientData ObjectType="Text">,将所有<x:ClientData ObjectType="Pdf">或者<x:ClientData ObjectType="Doc">的记录之前的第四条记录同时contest字段中含有“href="http://www.xxx.com/xxx”字符串的记录找出来，比如ID为29的那一条记录中contest字段中的内容是<x:ClientData ObjectType="Doc">,向上数4条，即ID为25的那一条记录，因为包含“href="http://www.xxx.com/”字符，所以ID为25的记录符合要求，被SELECT出来，同理ID为16的那条内容为“<x:ClientData ObjectType="Pdf">”的记录之上的第四条记录即ID为12的那条记录也符合这种情况。
如何将所以符合这种情况的记录全SELECT出来？