Hi Raj, those are two very diffrent entities, variables can be used in expressions, also in expressions configured for master items. Master items are a way of centralizing dimensions and measures.
I sometimes used master items that only contains a variable, and the variable contains the real expression. Master Items can be dragged to create new charts and variables not.
All about variables: Variables
An old video about master items:Creating Master Items (video)
Hi Raj ,
Variable and Master item both are different entity .If i explain in simple words.
Variable :Suppose you have one expression like "sum(Sales)" that you are going to use in other expression also, so rather then writing expression again and again ,we can create variable for expression sum(Sales) then we can use that variable in rest of the expression, where we want to use sum(Sales).
Master Item :Suppose you have created bar chart in one sheet ,if you want to use that bar chart again in same or different sheet,we have to copy that bar chart from one sheet to same sheet or different sheet but if you create master item once ,you can use that bar chart everywhere in our dashboard .just you have to drag and drop that bar chart from master item into sheet .