SQL Server String Aggregate functions

SqlServer has the following Aggregate functions: SUM, AVG, COUNT, COUNT (*), MAX, and MIN. However, all these functions can only aggregate numeric types and cannot aggregate strings.

SQL Server has the following Aggregate functions: SUM, AVG, COUNT, COUNT (*), MAX, and MIN. However, these functions can only aggregate value types and cannot aggregate strings.

See the following table: AggregationTable

If you want to obtain the aggregation result

SUM, AVG, COUNT, COUNT (*), MAX, and MIN cannot be used. These are the aggregation of values. However, we can solve this problem through user-defined functions.
1. First create a test table and insert the test data:
The Code is as follows:
Create table AggregationTable (Id int, [Name] varchar (10 ))
Go
Insert into AggregationTable
Select 1, 'zhao 'union all
Select 2, 'money' union all
Select 1, 'sun' union all
Select 1, 'lil' union all
Select 2, 'Week'
Go

2. Create a custom string Aggregate Function
The Code is as follows:
Create FUNCTION aggresponstring
(
@ Id int
)
RETURNS varchar (1024)
AS
BEGIN
Declare @ Str varchar (1024)
Set @ Str =''
Select @ Str = @ Str + [Name] from AggregationTable
Where [Id] = @ Id
Return @ Str
END
GO

3. Execute the following statement and view the result.
The Code is as follows:
Select dbo. aggresponstring (Id), Id from AggregationTable
Group by Id

Result: