In most Projects you will work in SAP there will be a requirement to find the following
Find SAP User id from Email address
Find Email Address from SAP User id.
Find Full name of a SAP User Id
Find Full name of Email address
With the introduction of out of the box CDS View you can find all the email addresses from SAP User Id with just one Select Statement.
The CDS View is PUSER002.
Go to SE11--> Enter Table PUSER002
You can check the field available after Displaying the CDS View
Now we can find the Full Name of user as well as email address attached to SAP User Master. Currently the SAP Email address that is maintained in PA0105 table for SAP User ID in Communication Infotype seems to be same in User Master in SU01D transaction Code.
You can use this solution in SAP ECC as well as SAP S/4HANA.
You can also create a Search help for this as this will make life easier for SAP End user and Consultants.