LINQ的书写格式如下:
from 临时变量 in 集合对象
where 条件表达式
[order by条件]
select 临时变量中被查询的值
[group by 条件]
Lambda表达式的书写格式如下:
集合对象.Where(临时变量=>(条件表达式))
Sql、Linq、Lambda 查询语句示例
1.查询Student表的所有记录
Sql:
select * from student
Linq:
from s in Students
select s
Lambda:
Students.Select( s => true)
2.查询Student表中的所有记录的Sname、Ssex和Class列。
Sql:
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})
3.查询教师所有的单位即不重复的Depart列。
Sql:
select distinct depart from teacher
Linq:
from t in Teachers.Distinct()
select t.DEPART
Lambda:
Teachers.Distinct().Select( t => t.DEPART)
4.查询Score表中成绩在60到80之间的所有记录。
Sql:
select * from score where degree between 60 and 80
Linq:
from s in Scores
where s.DEGREE >= 60 && s.DEGREE <