ApplyMap question

[Anonymous]

can I use ApplyMap when there is only "1" common id between two db tables (no excel files)?

Table A (the facts table):

  Contract_ID

Table B (table I am retrieving from):

  Contract_ID, Faults

I want to retrieve the record "if Faults = 't' in table B.   Can I do this or do I need to use Joins for this?

I have tried the following but it keeps looking for a file rather that recognising the tables. 

Mapping table as follows:-

AtFault_MappingTable:

Mapping LOAD

          training_contract_id,

          [at_fault]

from training_contract_returns

where at_fault = 't';

Load -

AtFault:

LOAD training_contract_id,

           at_fault,

           ApplyMap('AtFault_MappingTable',training_contract_id,'Nofault') as [AtFaultContractReturns]

from training_contract_returns;

[qlikviewwizard]

Glad to hear this. Please mark Correct Answer and Helpful to close the thread.

Regards,

Arjun

[avinashelite]

you can also try with the exist function too

[shair_abbas]

hey.
I have a simple question.
What is the reason of using mapping while you can get the desire results by just using joins?

[avinashelite]

when you have small amount of data their is not much difference between join and applymap but when you have huge data it has lot of impact with the performance . for eg say you need 3 to 4 columns from table 2 in table 1 , where table 1 have around 1 millions of records . In this case join is not ideal to use because it had huge impact on memory insted you can use the apply map 

[avinashelite]

check this thread

Joins Vs Applymap

[shair_abbas]

As you say if you need 3 to 4 columns from table 2 in table1 then you have to create 3 to 4 mapping load because in mapping load you just have two value one for look up other is return value.
so if same table is loaded 4 time and  searching in same table 4 time this will really harm the performance.

Although this is my opinion.
hope you find it helpful.

regards;

Syed Shair Abbas