关于SQL语句里面的A.XX,和B.select B.kecheng,B.score,B.xuehaofrom(select kecheng ,max(score) AS score from jiaScore group by kecheng) A,jiaScore Bwhere A.kecheng = B.kechengand A.score = B.score例如我这段数据库语句,A.kecheng和B.keche
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![关于SQL语句里面的A.XX,和B.select B.kecheng,B.score,B.xuehaofrom(select kecheng ,max(score) AS score from jiaScore group by kecheng) A,jiaScore Bwhere A.kecheng = B.kechengand A.score = B.score例如我这段数据库语句,A.kecheng和B.keche](/uploads/image/z/11061851-59-1.jpg?t=%E5%85%B3%E4%BA%8ESQL%E8%AF%AD%E5%8F%A5%E9%87%8C%E9%9D%A2%E7%9A%84A.XX%2C%E5%92%8CB.select+B.kecheng%2CB.score%2CB.xuehaofrom%28select+kecheng+%2Cmax%28score%29+AS+score+from+jiaScore+group+by+kecheng%29+A%2CjiaScore+Bwhere+A.kecheng+%3D+B.kechengand+A.score+%3D+B.score%E4%BE%8B%E5%A6%82%E6%88%91%E8%BF%99%E6%AE%B5%E6%95%B0%E6%8D%AE%E5%BA%93%E8%AF%AD%E5%8F%A5%2CA.kecheng%E5%92%8CB.keche)
关于SQL语句里面的A.XX,和B.select B.kecheng,B.score,B.xuehaofrom(select kecheng ,max(score) AS score from jiaScore group by kecheng) A,jiaScore Bwhere A.kecheng = B.kechengand A.score = B.score例如我这段数据库语句,A.kecheng和B.keche
关于SQL语句里面的A.XX,和B.
select B.kecheng,B.score,B.xuehao
from(select kecheng ,max(score) AS score from jiaScore group by kecheng) A,jiaScore B
where A.kecheng = B.kecheng
and A.score = B.score
例如我这段数据库语句,A.kecheng和B.kecheng 中的AB都是代表着什么?
关于SQL语句里面的A.XX,和B.select B.kecheng,B.score,B.xuehaofrom(select kecheng ,max(score) AS score from jiaScore group by kecheng) A,jiaScore Bwhere A.kecheng = B.kechengand A.score = B.score例如我这段数据库语句,A.kecheng和B.keche
A,B代表from后面的查询结果作为临时表、A,B为临时表的名字;
A.kecheng和B.kecheng代表查询结果集(临时表)中对应的字段;
说直接就是起别名、便于输入语句简单.
B.kecheng=jiaScore.kecheng
A.kecheng=(select kecheng ,max(score) AS score from jiaScore group by kecheng).kecheng