syntax error while creating a invoice

Hi I am new to this forum hope u guys can help me out,

I am ruuning following syntax for creating an invoice and for this error message is coming which is given below.

Select a_{adrnr a}stdc1 b~name1 into table inv_head1

From kna1 as a inner join adrc as b on a_{adrnr = b}addrnumber.

Unknown column name "A~STDC1" . field list. . field list. field list.