SQL Query to insert and get price within a range to length

Question

Lets say I have a range of length that have different price

Length      Price
0 - 10        18
11 - 15       20
16 - 20       30
21 - 40       45
41 - infinity 60

How should I store these information in database and how can I retrieve the information when let's say I enter length of 10.625 ? How can I get the price of the item with length of 10.625 ?

---

I not sure whether I already solved this problem or not

priceData.Length_End = Math.Ceiling(priceData.Length);

        string selectStatement = 
            "SELECT Price PriceList2 " +
            "WHERE @Length_End >= Length_Start AND @Length <= Length_End";

Then I get the first reader's value

SqlDataReader reader = selectCommand.ExecuteReader();
while (reader.Read())
{
   price = decimal.Parse(reader["Price_Per_Ton"].ToString());
   break;
}
reader.Close();

Please correct me if I was wrong. Thanks for all the responses!

Answer 1

Well , I believe you just need to store Length and you can use BETWEEN when you want to get Price column in your queries. Like;

Select Price
From YourTable
Where Length BETWEEN 11 AND 15

Here is SQL Fiddle Demo .

But this structure is ok only if you know maximum and minimum values of Length for each range. If you want to store them in database also, you should seperate two different columns your Length column. Like;

Max_Length | Min_Length | Price
0          | 10         | 18
11         | 15         | 20 
16         | 20         | 30
21         | 40         | 45
41         |            | 60

---

Select Price
From YourTable
Where Min_Length < 10.625 AND Max_Length > 10.625

Answer 2

you can change the structure to:

len_start    len_end      price
0            10           18
11           15           20
16           20           30
21           40           45
41           infinity     60

and run query like:

declare @len decimal
set @len= 10.615

select price from table
Where len_start <= @len and @len < len_end

if you are going to use NULL as infinity, run this query:

select price from table
Where (len_end is not null AND len_start <= @len and @len < len_end) OR 
      (len_end is null AND len_start <= @len)