How can i select from more than one table in a SqlDataSource asp.net

Question

i have a web page, that will load data from three tables is there a way to load all the data at once using a Sqldatasource, or must i do it in coding?

i also want to sort it. but that i know how to do. and all the data goes into a gridview, which is why i want to use just one Sqldatasource.

this is what i have so far:

<asp:SqlDataSource ID="SqlDataSource1" runat="server" ConnectionString="<%$ 
ConnectionStrings:testpicsConnectionString %>" SelectCommand="SELECT * FROM [tball]
select * from tb1
select * from tb2"></asp:SqlDataSource>

and do i just add

sort id desc

to them all?

i just want to know can it be done with one Sqldatasource?

btw, I'm using c# and sql (obviously)

sorry forgot to add the schema from the tables

all the tables are the same: they have id, desc and pic

id int primary key identity not null,
[desc] varchar(max) null,
pic varbinary(max) null

that is used for all tables. so if i had to join, on where or what would i join?

Answer 1

you could use UNION to select the columns from the different tables...

select * from tb1
union all 
select * from tb2
union all
select * from tb3
order by id desc;

---

union all - will show all records in your result.
union - will remove duplicate records from your result.

Union all will give better performance as the database engine won't have any overhead for managing the result to remove the duplicates.

Answer 2

You can also create a view in your database that will collect all the data you need and then query it in your c# application.

Answer 3

Go here: Union

select * from Table1 union all select * from Table2 order by 1