我的错误在哪儿？关于SQL语句语法

Question

sStr:='Select * From '''+tablenames+''''; 

Answer 1

sStr:='Select * From '+tablenames;

Answer 2

sstr:='select * from '+tablenames;
query1.close;
query1.clear;
query1.sql.add(sstr);
query1.open;query1.close;
query1.clear;
query1.sql.add('select * from'+tablenames);
query1.open;

Answer 3

sStr:='Select * From "'+tablenames+'"'; //就是这儿错了；去掉后边的引号
就可以啦；
tablenames本来就是一个字符串型，你加引号反而是给加错了；
去了就行啦！`

Answer 4

sStr:String; 
tablenames:String; sStr:='Select * From '+tablenames+''; 
Query1.Close; 
Query1.Clear; 
Query1.SQL.Add(sStr); 
Query1.Open; 

Answer 5

procedure TForm1.Button1Click(Sender: TObject);
var
str:string;
begin
query1.close;
str:='tablenames';
query1.SQL.Add('select * from '+str);
query1.ExecSQL;
query1.Active:=TRUE;
end;

Answer 6

sStr:String;
tablenames:String;sStr:='Select * From tablenames';
Query1.Close;
Query1.Clear;
Query1.SQL.Add(sStr);
Query1.Open