@echo off
if "%~1"=="" goto :next
echo %sql% | isql -quiet
goto :eof

:next
setlocal
set fbdb=localhost/gds_db:mydb
set fbuser=SYSDBA
set fbpass=masterke
set sql=SET SQL DIALECT 3;
set sql=%sql%CONNECT '%fbdb%' USER '%fbuser%' PASSWORD '%fbpass%';
set sql=%sql%SELECT CURRENT_TIMESTAMP FROM RDB$DATABASE;
set sql=%sql%COMMIT WORK;
set sql=%sql%QUIT;
for /f "tokens=1,2 skip=4" %%i in ('call "%~0" do_sql') do (
  set dbdate=%%i
  set dbtime=%%j
)
echo dbDate: %dbdate%
echo dbTime: %dbtime%
endlocal
goto :eof