Question[SQL]：Can you use a SQL statement to calculating it!

Question：Can you use a SQL statement to calculating it!

How can I print "10 to 20" for books that sell for between $10 and $20，"unknown" for books whose price is null, and "other" for all other prices?

Answer：

    if OBJECT_ID('dbo.Table101301') is not null
        drop table dbo.Table101301
    create table dbo.Table101301
    (
        [bookid] int not null,
        [bookname] varchar(10),
        [price] varchar(10) 
    )
    insert into dbo.Table101301 values(1,'book1', 1)
    insert into dbo.Table101301 values(2,'book2', 5)
    insert into dbo.Table101301 values(3,'book3', 8)
    insert into dbo.Table101301 values(4,'book4', 10)
    insert into dbo.Table101301 values(5,'book5', 12)
    insert into dbo.Table101301 values(6,'book6', null)
    insert into dbo.Table101301 values(7,'book7', 20)
    insert into dbo.Table101301 values(8,'book8', 21)
    insert into dbo.Table101301 values(9,'book9', null)
    
    select [bookid], [bookname],
        [price] = (
            case 
                when [price]  is null then 'unknown' 
                when [price] between 10 and 20 then '10 to 20'
                else [price]
            end 
        )
        from dbo.Table101301    
    
    drop table dbo.Table101301