我在mySQL db上有这样的表:
Olimpiade Sport Disciplina Categoria
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London 2012 Athletics 100m men
London 2012 Athletics 100m woman
Beijing 2008 Athletics 200m men
Beijing 2008 Athletics 200m women
Athens 2004 Athletics 800m men
Athens 2004 Athletics 800m women
等等.我不知道我是否可以设置这样的查询,但我想得到的结果如下:
Disciplina Categoria London 2012 Beijing 2008 Athens 2004
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100m men yes no yes
100m women yes yes no
200m men yes no yes
200m women yes yes no
800m men yes yes yes
800m women yes yes yes
那就是奥林匹克版的试验是否存在.