1> list_to_binary(["select * from aa limit","1",",","97"]).
<<"select * from aa limit1,97">>
2> list_to_binary(["select * from aa limit",integer_to_list(1),",","97"]).
<<"select * from aa limit1,97">>
3> list_to_binary(["select * from aa limit",1,"97"]).
<<115,101,108,101,99,116,32,42,32,102,114,111,109,32,97,
97,32,108,105,109,105,116,1,57,55>>
不理解：第三中的那个 “1”有点不理解。