select id from (select id from pedigree group by number having count(name)>1)as a; 为啥用as a

$query = mysql_query( select * from 表名 where id='$_GET[id]' )中'$_GET[id]'是什么意思? 请问sql=select * from 招聘信息 order by id select id from (select id from pedigree group by number having count(name)>1)as a; 为啥用as a select id,name from student where id in ( select id from score having count(id)>=2 );以上这段语句有没语法错误.SQL语句 select top 1 ID from Net_dictionary,其中top1 ID指的是什么? sql语句：去掉最大值,去掉最小值,算平均值SELECT AVG(Scores.Score)FROM ScoresWHERE ( ( (Scores.[ID]) = @id)AND (Score < (SELECT MAX(Score) From Scores WHERE Scores.[ID] = @id) )AND (Score > (SELECT MIN(Score) From Scores WHERE Scores.[I 请教sql语句,像select …from wsdy_zb t where t.id =:id order by no desc 中t.id =:id select ** from A where A.id in (select id from B where ****) 在以下哪种情况,select ** from A whereselect ** from A where A.id in (select id from B where ****) 在以下哪种情况,此语句执行的速度快：（1）A表的记录数远多于 为什么 select * from student left outer join takes on true where student.id=takes.id; 运行不了为什么 select * from student left outer join takes on true where student.id=takes.id; 运行不了 这是书上的 谁能帮我挑挑错?mycmd.CommandText = select id from & m1_TableName & where id=' & ddlid.SelectedItem.Text & ' select * from table_a a where a.id not in (id1,id2,id3.) 中的id可以放置多少个? select.where...in的作用select * from pirce where id in (16,3,17,18,73) in的作用是什么是不是查询id在IN中的数据? SQL语句理解 select * from B where (select count(1) as num from A where A.ID = B.ID) = 0select * from B where (select count(1) as num from A where A.ID = B.ID) = 0请问如何理解,为什么 可以在B表中 排除A表的数据 select count(*) as total from 'test' order by id desc 希望得到正解 nsql=select * from gonggao where passed=1 order by id desc oracle sql语句获取前两条数据select id,seq from hzds_admin where seq select Field_Content,ID*1 as ID,[index]=identity(int,1,1) into #temp from user_Pro where categoryid= + id+ order by indexid desc; select * from #temp; drop table #temp; select Field_Content,ID*1 as ID,[index]=identity(int,1,1) into #temp from user_Pro where categoryid= + id+ order by indexid desc; select * from #temp; drop table #temp;