How can I select data in LinQ

Question

1.00/5 (1 vote)

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I have tables here

SQL

create table Product(
Pro_id int primary key,
Pro_Name varchar(50)
)

create table Order(
Order_id int primary key,
Pro_id int foreign key references Product(Pro_id),
DateOfOrder Date,
Quantity int check(Quantity > 0)
)

How can I select "Pro_Name" that is ordered and "all of record in table Orde"r (using LinQ)?

Posted 15-Apr-15 3:00am

Bùi Long Nghĩa

Updated 15-Apr-15 14:46pm

v3

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Peter Leow · Accepted Answer · 2015-04-15T03:13:00

Solution 1

Learn to do it yourself:
LINQ (Language-Integrated Query)[^]

Posted 15-Apr-15 3:13am

Peter Leow

John C Rayan · Accepted Answer · 2015-04-15T03:20:00

Solution 2

You would require something like this

SQL

var p =   (from o in db.Order
          join prod in db.Product
          on o.pro_id equals prod.pro_id
          orderby prod.pro_name
          select new
          {
            prod.pro_name,
            o.dateoforder,
            o.quantity,
            o.order_id
          });

Posted 15-Apr-15 3:20am

John C Rayan

Updated 15-Apr-15 21:51pm

v2

Comments

Sascha Lefèvre 15-Apr-15 9:22am

You don't need to "select new" if you only select one field. Just select prod.pro_name

John C Rayan 15-Apr-15 9:28am

I agree and as I said in my solution "something like this". It depends how the op implements in the code. Thanks anyway.

Bùi Long Nghĩa 15-Apr-15 20:17pm

Thanks. You know that if I just select from the table Product, I will not be able to know what products are ordered.

John C Rayan 16-Apr-15 1:52am

Because the product from order table joined with product table you will see only the products that are ordered

Bùi Long Nghĩa 16-Apr-15 2:38am

How can I do if I want to select "Pro_Name" and all of column in table Order?

John C Rayan 16-Apr-15 3:52am

Check my updated solution.

Bùi Long Nghĩa 16-Apr-15 5:24am

Thanks so much.

John C Rayan 16-Apr-15 5:53am

Remember to mark the solution as accepted.

George Swan · Accepted Answer · 2015-04-15T08:06:00

Solution 3

C#

//An alternative in fluent syntax
var pro_names = db.Order.Join(db.Product,o=>o.pro_id,p=>p.pro_id,(o,p)=>new {p.pro_name}).
OrderBy(a=>a.pro_name);

Posted 15-Apr-15 8:06am

George Swan