System Variable are predefined in SAP
SYST is the Structure for the system Field
All system fields are addressed using SY field
The Various are as follows
SY-SUBRC - system variable for return code (Successful =0 , not Successful =Other than 0)
SY-TABIX -Returns current line index inside a loop in Internal table
SY-INDEX - Returns current line index inside DO While loop
SY-DATUM - system Variable for current Date Format (yyyymmdd)
SY-UNAME - LOG ON Name of the User
SY-UZEIT - It returns the current system time
