Inno Setup & MySQL

To start mysql as service from Inno Setup installer you can use this code:

[Run]
Filename: {app}\bin\mysqld; Parameters: --install; WorkingDir: {app}\bin;  
 Flags: postinstall runhidden; StatusMsg: MySQL service installing; 
 AfterInstall: InitializeService;

[Code]
procedure InitializeService();
var
    ErrorCode: Integer;
begin
 ShellExec('', ExpandConstant('{sys}\net.exe'),' start mysql', '', 
  SW_SHOW, ewNoWait, ErrorCode);
end;