表table1,有xb字段（男、女），如何用一条select语句统计该表的总人数、男生人数、女生人数各为多少，以便显示于grid的同一行？Access数据库.
为何以下查询，查出来有多条结果记录：
select (select count(*) from able1) as 总人数 , (select count(*) from able1where xb='男') as 男生人数,(select count(*) from able1where xb='女') as 女生人数 from able1谢谢……
为何以下查询，查出来有多条结果记录：
select (select count(*) from able1) as 总人数 , (select count(*) from able1where xb='男') as 男生人数,(select count(*) from able1where xb='女') as 女生人数 from able1谢谢……
select count(*) as 总人数 , (select count(*) from able1where xb='男') as 男生人数,(select count(*) from able1where xb='女') as 女生人数 from able1