Lookup based on result from another lookup

Question

I have a table that returns MID based on a concat of id and csid that are in my list. This works as it should.

Can I use the mid to do a lookup on another data extension to return an address? If so, how do i do it?

Table 1

idcsid	mid
142	1001
242	1002
345	1003
485	1004
5245	1005
1245	1006

script

%%[ 

Var @id, @csid, @aidcsid, @idcsid,@mid, @row, @rows,@rowcount

Set @id = AttributeValue("id") 
Set @csid = AttributeValue("csid") 
Set @aidcsid = Concat(@id,@csid) 
Set @rows = LookupRows("mid", "idcsid", @aidcsid) 
set @rowCount = rowcount(@rows) 


if @rowCount > 0 then set @row = row(@rows,1) 

set @decid = field(@row,"mid") 

 ]%% 

That works as it should.

I want to have another Data Extension that I can lookup based on mid. Is this possible?

mid = the derived value based on the previous lookup
csid = attribute value
lang = attribute value
addy = The field I need to return,

So the lookup will be on a concat of mid, csid, lang and then it returns addy.

Table 2

mid	csid	lang	address
1001	42	en	address in english
1001	42	pt	address in portuguese
1001	42	it	address in italian
1001	94	en	address in english
1001	94	pt	address in portuguese
1001	94	it	address in italian

Answer 1

You should be able to just do a lookup or lookuprows using the 3 values as the conditions. I used a simple 'lookup' instead of a lookuprows as you only needed a single value and it looks like its a 1:1 match, so should not need to have consideration of multiple row returns. I also changed your current lookuprows to lookup.

%%[ 

Set @lang = AttributeValue("lang")
Set @id = AttributeValue("id") 
Set @csid = AttributeValue("csid") 
Set @aidcsid = Concat(@id,@csid) 
Set @decid = Lookup("Table1", "mid", "idcsid", @aidcsid) 

IF NOT EMPTY(@decid) THEN
  set @address = Lookup("Table2","address","mid",@decid,"csid",@csid,"lang",@lang)
ENDIF

 ]%% 

I added in the setting of @lang and used Table1 and Table2 as the DE names. Other than adjusting those to the correct context, the above should work for your needs.