sql server - Get all records in SQL depending on user input -

i learning sql , came across difficulty. data table looks this

dbo data

id | name | surname | title  | location ---------------------------------------- 1  | xxx  | abc     | def    | london 2  | xxx  | abc     | def    | oslo 3  | xxx  | abc     | def    | new york 

now want id, name, title , surname , use query this:

select      id, name, surname, title       data       location = 'london' -- (this user input) 

but problem if user inputs all or world or empty string in where clause, want query return rows. possible writing query handle special scenarios above????

i using asp.net datasource

<asp:sqldatasource id="sqldatasource1" runat="server"       connectionstring="<%$ connectionstrings:mainconnectionstring %>"       selectcommand="select [name], [id], [surname], [title] [data] [location] = @location)" >    <selectparameters>        <asp:controlparameter controlid="label1" name="location"              propertyname="text" type="string" />    </selectparameters> </asp:sqldatasource>` 

the input depends on route path of url localhost:56789/people/london/

the corresponding vb file

protected sub page_load(sender object, e eventargs) handles me.load     if (request.pathinfo.length = 0)      else         dim t = request.pathinfo.substring(1)         label1.text = t     end if end sub 

i know can application side curios if possible in query itself.

if want in query, try this:

select      id, name, surname, tittle       data       location = <input> or     <input> in ('all', 'world', '')