QUERY REGARDING FETCHING AND JOIN

Hi All!

I am doing an assignment in which I take an input from user for the corresponding fields:

TVKO-VKORG

TVTW-VTWEG

TSPA-SPART

VBAK-ERDAT

VBAK-VBELN

KNA1-KUNNR

and after that, I print a list containing corresponding values from the following fields:

VBAP-VBELN

VBAP-POSNR

VBAP-MATNR

VBAP-ARKTX

VBAP-KWMENG

VBAP-VRKME

VBAP-NETWR

VBAK-WAERK

All the tables mentioned here have one key field MANDT in common. How do I map the input values with the values to be displayed in the final list? How do I determine if joining is necessary?