How to append values from data extension to url?

Question

We have a landing page that exists within our ExactTarget account and we would like to pass values to an external landing page. Is there a way, either through the url or another method, to pass multiple values to an external landing page? Sample data would be:

Patient1 ID, Patient1 Action, Patient2 ID, Patient2 Action

Answer 1

Sure. You can just do a string concat() of the URL parameters based on some data source:

%%[
var @rows, @row, @rowCount, @numRows, @zip, @i, @url

set @zip = "55555"
set @numRows = 0 /* 0 means all */
set @rows = LookupOrderedRows("PatientInfo",@numRows,"patientID desc, patientAction asc","patientZip", @zip)
set @rowCount = rowcount(@rows)

if @rowCount > 0 then

    set @url = "http://externalurl.com"

    for @i = 1 to @rowCount do

        var @patientID, @patientAction
        set @row = row(@rows,@i) 
        set @patientID = field(@row,"patientID")
        set @patientAction = field(@row,"patientAction")

        set @url = iif(@i==1,concat(@url,"?"),concat(@url,"&"))
        set @url = concat(@url,"patient",@i,"ID=", @patientID)
        set @url = concat(@url,"&patient",@i,"Action=", @patientAction)

    next @i 
else
    outputLine(concat("No patients found"))
endif 

]%%
<a href="%%=redirectto(@url)=%%">external URL</a>