1、 查询Student表中的所有记录的Sname、Ssex和Class列。
select sname,ssex,class from student
Linq:
from s in Students
select new {
s.SNAME,
s.SSEX,
s.CLASS
}
Lambda:
Students.Select( s => new {
SNAME = s.SNAME,SSEX = s.SSEX,CLASS = s.CLASS
})
2、 查询教师所有的单位即不重复的Depart列。
select distinct depart from teacher
Linq:
from t in Teachers.Distinct()
select t.DEPART
Lambda:
Teachers.Select( t => t.DEPART).Distinct()
13、查询最低分大于70，最高分小于90的Sno列。
select sno from score group by sno having min(degree) > 70 and max(degree) < 90
Linq:
from s in Scores
group s by s.SNO
into ss
where ss.Min(cc => cc.DEGREE) > 70 && ss.Max( cc => cc.DEGREE) < 90
select new
{
sno = ss.Key
}
Lambda:
Scores.GroupBy (s => s.SNO)
.Where (ss => ((ss.Min (cc => cc.DEGREE) > 70) && (ss.Max (cc => cc.DEGREE) < 90)))
.Select ( ss => new {
sno = ss.Key
})
14、查询所有学生的Sname、Cno和Degree列。
select s.sname,sc.cno,sc.degree from student as s,score as sc where s.sno = sc.sno
Linq:
from s in Students
join sc in Scores
on s.SNO equals sc.SNO
select new
{
s.SNAME,
sc.CNO,
sc.DEGREE
}
Lambda:
Students.Join(Scores, s => s.SNO,
sc => sc.SNO,
(s,sc) => new{
SNAME = s.SNAME,
CNO = sc.CNO,
DEGREE = sc.DEGREE
})
15、查询所有学生的Sno、Cname和Degree列。
select sc.sno,c.cname,sc.degree from course as c,score as sc where c.cno = sc.cno
Linq:
from c in Courses
join sc in Scores
on c.CNO equals sc.CNO
select new
{
sc.SNO,c.CNAME,sc.DEGREE
}
Lambda:
Courses.Join ( Scores, c => c.CNO,
sc => sc.CNO,
(c, sc) => new
{
SNO = sc.SNO,
CNAME = c.CNAME,
DEGREE = sc.DEGREE
})
16、查询所有学生的Sname、Cname和Degree列。
select s.sname,c.cname,sc.degree from student as s,course as c,score as sc where s.sno = sc.sno and c.cno = sc.cno
Linq:
from s in Students
from c in Courses
from sc in Scores
where s.SNO == sc.SNO && c.CNO == sc.CNO
select new { s.SNAME,c.CNAME,sc.DEGREE }