请大家捉虫子!!!

Question

query1.close;
query1.sql.Clear;
query1.sql.add('Select Sum(ylrk.yljs) ');
query1.sql.add('(Select Sum(ckjs) From ylck Where ylbh=ylrk.ylbh) ');
query1.sql.add('(Select Sum(yljs) From ylrk Where rq<=:rq2 and ylbh=ylrk.ylbh Group By ylbh)-');
query1.sql.add('(Select Sum(ckjs) From ylck Where rq<=:rq2 and ylbh=ylrk.ylbh Group By ylbh)');
query1.sql.add('From ylrk ');
query1.sql.add('Where (ylrk.rq>=:rq1) and (ylrk.rq<=:rq2)');
query1.sql.add('Group By ylrk.ylbh');
query1.Parameters.ParamByName('rq1').value:=rq1.datetime;
query1.Parameters.ParamByName('rq2').value:=rq2.datetime;
query1.prepared;
query1.Open;

Answer 1

错误信息是什么？
建议：放在Delphi中调试，不必在网页

Answer 2

query1.close;
query1.sql.Clear;
query1.sql.add('Select Sum(ylrk.yljs) ');
query1.sql.add('(Select Sum(ckjs) From ylck Where ylbh=ylrk.ylbh) ');
query1.sql.add('(Select Sum(yljs) From ylrk Where rq<=:rq20 and ylbh=ylrk.ylbh Group By ylbh)-');
query1.sql.add('(Select Sum(ckjs) From ylck Where rq<=:rq21 and ylbh=ylrk.ylbh Group By ylbh)');
query1.sql.add('From ylrk ');
query1.sql.add('Where (ylrk.rq>=:rq1) and (ylrk.rq<=:rq22)');
query1.sql.add('Group By ylrk.ylbh');
query1.Parameters.ParamByName('rq1').value:=rq1.datetime;
query1.Parameters.ParamByName('rq20').value:=rq2.datetime;
query1.Parameters.ParamByName('rq21').value:=rq2.datetime;
query1.Parameters.ParamByName('rq21').value:=rq2.datetime;
query1.prepared;
query1.Open; 

Answer 3

可以在select后加子查询吗？好象不行吧