Three types of user-defined functions for SQL Server

Create function fun_a () #标题函数, create function Fun_name () returns OUTPUT_TYPE as begin return value end;
returns int
As
Begin
return 1;
End
Go

Create function Fun_b () #多语句用户定义函数, create function Fun_name () returns @value table (Colum_list) as begin return; end
Returns @tb table (ID int, Name nvarchar (8))
As
Begin
Insert into @tb (id,name) VALUES (1, ' 111 '), (2, ' 222 ');
Return
End
Go

Create function Fun_c () #内联用户定义函数, create function Fun_name () returns table as return select ...;
Returns table
As
Return select 1 as a,2 as b,3 as C;
Go

Three types of user-defined functions for SQL Server