sqlserver自定义函数的创建与调用

表值函数-内嵌函数：

1 create function 函数名（参数）
2 returns table 
3 [with {Encryption | Schemabinding }]
4 as 
5 return(一条SQL语句)

表值函数-多语句函数：

1 create function 函数名（参数）
2    returns 表变量名 table (表变量定义)
3    [with {Encryption | Schemabinding }]
4 as 
5    begin
6     SQL语句
7    end 

下面介绍使用方法，使用前先创建几个表用于测试，表如下：

 1 CREATE TABLE [dbo].[Classes](
 2     [ID] [int] IDENTITY(1,1) NOT NULL primary key,
 3     [ClassName] [nvarchar](50) NOT NULL,
 4     [CreateTime] [datetime] NOT NULL
 5     );
 6 
 7     CREATE TABLE [dbo].[Students](
 8     [ID] [int] IDENTITY(1,1) NOT NULL primary key,
 9     [Name] [nvarchar](50) NOT NULL,
10     [ClassId] [int] NOT NULL,
11     [Age] [int] NOT NULL,
12     [CreateTime] [datetime] NOT NULL
13     );
14 
15     CREATE TABLE [dbo].[Courses](
16     [ID] [int] IDENTITY(1,1) NOT NULL primary key,
17     [Name] [nvarchar](50) NOT NULL,
18     [Credit] [float] NOT NULL
19     );
20 
21     CREATE TABLE [dbo].[StuScores](
22     [ID] [int] IDENTITY(1,1) NOT NULL primary key,
23     [StuId] [int] NOT NULL,
24     [CourseId] [int] NOT NULL,
25     [Score] [int] NOT NULL
26     );

例子如下：

 1 --标量函数：返回某个班级的人数
 2 create function F_GetSomeClassStuCount(@classId int)
 3 returns int
 4 as
 5 begin
 6 declare @rtnCount int
 7 select @rtnCount=count(*) from Students where ClassId=@classId
 8 return @rtnCount
 9 end;
10 
11 select dbo.F_GetSomeClassStuCount(1);
12 
13 --表值函数-内嵌函数：返回某个班级的人员信息  注意此处不需begin-end包裹
14 create function F_GetSomeClassStruInfo(@classId int)
15 returns table
16 as 
17 return (select * from Students where ClassId=@classId);
18 
19 select * from dbo.F_GetSomeClassStruInfo(1);
20 
21 --表值函数-多语句函数：返回某个学生的成绩
22 create function F_GetSomStuScore(@stuName nvarchar(50))
23 returns @tmpTb table(
24 StuName nvarchar(50),
25 CourseName nvarchar(50),
26 Score int
27 )
28 as
29 begin
30 insert into @tmpTb
31 select s.Name as StuName,c.Name as CourseName,ss.Score
32 from StuScores ss
33 left join Students s on ss.StuId=s.ID
34 left join Courses c on ss.CourseId=c.ID
35 where s.Name=@stuName
36 return
37 end;
38 
39 select * from F_GetSomStuScore(‘杨过‘)

sqlserver自定义函数的创建与调用

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