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  ID SEX SCORE YEAR
  1 ÄÐ 88 2007
2 Å® 87 2008
3 ÄÐ 89 2006
4 Å® 99 2009
5 ÄÐ 54 2007
6 Å® 56 2008

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select count(*) from student;
select count(*) from student where sex='ÄÐ';
select count(*) from student where sex='Å®';

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SQL code:

select sex,count(*) from student group by sex
select count(*) as ×ÜÈËÊý from student


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select count(*) from student;
select count(*) from student where sex='ÄÐ';
select count(*) from student where sex='Å®';

ÊDzÉÓÃÒ»ÌõÓï¾äÕ¹ÏÖ³öÉÏÃæµÄͳ¼Æ½á¹û ¼´£º count£¨*£©£¬count(ÄÐ)£¬count£¨Å®£© ÕâÑùµÄЧ¹û

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SQL code

select sex,count(*) from student group by sex
select count(*) as ×ÜÈËÊý from student


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²»ÊÇÓÃÁ½ÌõÓï¾ä

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select (select count(*) from student) as total,(select count(*) from student where sex='ÄÐ') as mens,(select count(*) from student where sex='Å®') as womens from student;

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SQL code

select count(*) ×ÜÈËÊý,
sum(case when sex=