When can RELATED be omited?

[Anonymous]

Is there any differnce in using RELATED or not for the below case? I still cannot follow when its necesary to use it, for example:

VAR = SELECTCOLUMNS(  FILTER(Cust,Cust[City] = "LA")
                                          ,"CustNo"
                                         ,Cust[CustNo] )

Works the same as...

VAR =
SELECTCOLUMNS(

  FILTER(
              Cust
              ,RELATED(Cust[City]) = "LA"

             )
  ,"CustNo"
  ,Cust[CustNo]
)

[Anonymous]

@Anonymous 

RELATED is needed only if the following conditions hold simultaneously:

1. You've got a row context on a certain base table.

2. You want to get a value from a table that is in relation to the one you are iterating over right now (hence the row context) and the table sits on the one-side of the relationship.

This is really all there is to it. Please read the documentation of the function as well https://dax.guide/related 

[amitchandak]

@Anonymous , if you are using cust table, then there is no need to use related. You should use that to bring column from a table from one side of one to many join

refer: https://www.youtube.com/watch?v=Wu1mWxR23jU