name         nun         date
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h1           1002        2004-1-1  
h2           1000        2004-2-1
h3           1005        2004-3-1
h1           1003        2004-1-5
h2           1008        2004-1-9
h6           1004        2004-5-1
h2           1010        2004-10-1找出表内唯一的,并且是 nun 值是最大的记录,即结果如下:name         nun         date
----------------------------------
h3           1005        2004-3-1
h1           1003        2004-1-5
h6           1004        2004-5-1
h2           1010        2004-10-1这语句怎写?