LOOKUP Function in Sql server Reporting Services-SSRS

How works Lookup in SSRS

I am taking one Emp table and One Dept table like bellow

Emp Table :-    Some Employee have no departments  did is NULL

 

Dept Table:-  Hear 5 departments but matched to Emp table only 4 dept

In Reporting Services I am taking two (2) different sources and two different data sets

Dataset 1 = EMP

 

 

 

Dataset2 : DEPT

 

 

I am using two data sources for each Each dataset individually

      

                

Hear in the Dname level field I am written a lookup expression

LOOKUP Expression:-  Right Click and Go to Expression  and write lookup Expression

Then Click ok and select preview

Hear Display only full rows in employee table and matched rows in Dept table 

In My DEPT Table have 5 Record not matched to Dept  , That Record not display hear

And hear displayed all records in EMP data set

 

 

Thank you J

 Sankar