SQL查询以从学生和分数表中获取数据

我有两张桌子和两本书

学生：sid编号，sname varchar3

sid sname
---------
 4   abc
 2   def
 1   ghi
 3   jkl

图书：sid编号，图书varchar1

sid  book
---------
 3    a
 2    b
 2    c
 1    u
 4    d
 1    k
 3    p
 4    q
 4    k

现在，我想要如下所示的输出sid、sname和每个学生阅读的书籍数量

sid sname count
---------------
 1   ghi    2
 2   def    2
 3   jkl    2
 4   abc    3

请帮我解决这个问题。

只需在sid列中加入两个

请尝试此查询一次

 select * into #student from(
 select 4   s_id,'abc' as name
 union all
 select 2   ,'def'
 union all
 select 1   ,'ghi'union all
 select  3   ,'jkl'
 ) as a

 drop table #student
  select * into #books from(

  select 3    s_id,'a' as book
   union all
 select 2    ,'b'
 union all
 select  2  ,  'c'union all
 select  1  ,  'u'union all
 select  4   , 'd'union all
 select  1    ,'k'union all
 select  3    ,'p'union all
 select  4    ,'q'union all
 select  4    ,'k'
 ) as a

 select * from #student
 select * from #books


  select s.s_id,s.name,COUNT(b.s_id) as[count] from #student s
  inner join #books b on b.s_id=s.s_id
  group by s.s_id,s.name

结果输出如下

  +------+------+-------+
| s_id | name | count |
+------+------+-------+
|    1 | ghi  |     2 |
|    2 | def  |     2 |
|    3 | jkl  |     2 |
|    4 | abc  |     3 |
+------+------+-------+

---

`选择sname，cnt from students s join选择sid，按s.sid=b.sid；上的sid b将*计为cnt from books group好吗？@Raaki你在评论中提出了不完整的问题，但我明白了。您希望先聚合，然后加入。它将产生与学生表相同的结果，或者至少应该有唯一的学生。只是键入@GurV。现在请检查完整的结果query@Raaki这将与我的查询做相同的事情。最好在代码中包含一些上下文/解释，因为这会使答案对OP和未来的读者更有用。您可以随时编辑你的问题没有得到回答吗？

 select * into #student from(
 select 4   s_id,'abc' as name
 union all
 select 2   ,'def'
 union all
 select 1   ,'ghi'union all
 select  3   ,'jkl'
 ) as a

 drop table #student
  select * into #books from(

  select 3    s_id,'a' as book
   union all
 select 2    ,'b'
 union all
 select  2  ,  'c'union all
 select  1  ,  'u'union all
 select  4   , 'd'union all
 select  1    ,'k'union all
 select  3    ,'p'union all
 select  4    ,'q'union all
 select  4    ,'k'
 ) as a

 select * from #student
 select * from #books


  select s.s_id,s.name,COUNT(b.s_id) as[count] from #student s
  inner join #books b on b.s_id=s.s_id
  group by s.s_id,s.name

  +------+------+-------+
| s_id | name | count |
+------+------+-------+
|    1 | ghi  |     2 |
|    2 | def  |     2 |
|    3 | jkl  |     2 |
|    4 | abc  |     3 |
+------+------+-------+