i have this internal table
types:begin of y_lt_display,
bldat type mkpf-bldat,
end of y_lt_display.
types:begin of y_lt_lfa1,
name1 type lfa1-name1,
end of y_lt_lfa1.
types:begin of y_lt_mseg,
menge type mseg-menge,
end of y_lt_mseg.
i want to add the field name1 and meng from lfa1 and mseg to tthe internal table y_li_display.how to do