error: String and Byte Incompatible

Question

While compiling my code, it produces "Incompatible types: 'String' and 'Byte'. I do not see where I define variable as byte.

unitB

function TDatabaseManager.getPortType(portNo:string):String;
var
   SQLQuery:TSQLQuery;
begin
   result := '';
   SQLQuery := TSQLQuery.Create(Nil);
try
    SQLQuery.SQLConnection := FSQLConnection;
    SQLQuery.SQL.Clear;
    SQLQuery.SQL.Text:= 'SELECT '+portNo+' FROM tblmk6ecpu_setupindex AS t1, tblmk6ecpu_setup AS t2';
    SQLQuery.SQL.Text := SQLQuery.SQL.Text + ' WHERE t1.BatchNumber = '''+BatchNo+ ''' AND t1.MfgCode = t2.MfgCode';
    SQLQuery.SQL.Text := SQLQuery.SQL.Text + ' ORDER By t1.SetupId DESC';
    SQLQuery.Active:=true;
    if (not(SQLQuery.IsEmpty())) then
        result := VarToStr(SQLQuery.FieldValues[portNo]);
finally
    SQLQuery.free;
end;
end;

unitA

for i:= 1 to 10 do
    begin
      portType:=TDatabaseManager.getPortType('Port'+i);
    end;

Please advise

Answer 1

In this line:

getPortType('Port'+i);

You are trying to append an integer directly to a string literal. That does not work. You need to change it to this instead:

getPortType('Port'+IntToStr(i));