how to write a sql query with multiple variables

sir, i want to write a SQLquery in which in the where clause i use two variables on two fields.

i tried the following, but getting error messages.

let
x=1;    % Variable1
y=4;    % Variable2.
curs=exec(conn,['select all from _tablename_ where field1=',num2str(x),and 'field2=',num2str(y)]);
curs=fetch(curs);

I am getting error message.

please guide me.

[Stephen23]

@Mechanical Engineering: please give us the complete error message. This means all of the red text.