Question

delphi 中如何用 sql语句中like实现复选框的查询功能(模糊）

用CHECKBOX这个控件怎么写程序呢？按以下代码写的程序出现的问题是：
只要是查询项，无论选没选，在数据库中是空的记录都查不出来。谢谢！
procedure TForm19.Button3Click(Sender: TObject);
var YBXH,WH,YBMC,QH,CDMC,......:string;
begin
YBXH:='%';WH:='%';QH:='%';CDMC:='%';TUNIT:='%';YBMC:='%';
......
if CheckBox1.Checked=true then YBXH:=edit3.Text;
if CheckBox2.Checked=true then WH:=edit27.Text;
if CheckBox3.Checked=true then YBMC:=wwDBLookupCombo5.text;
......
WITH wwQuery1 DO
begin
close;
sql.clear;
sql.Add('select * from ybtz');
sql.add('where YBXH like :YBXH and WH like :WH and YBMC like :YBMC and QH like :QH ');
sql.add(' and GGLC like :GGLC and LB like :LB and GLZT like :GLZT and CDMC like :CDMC and UNIT like :TUNIT and SX like :SX');
sql.Add('order by WH,YBMC');
paramByName('YBXH').asstring:='%'+YBXH+'%';
paramByName('WH').asstring:='%'+WH+'%';
......
open;
end;

Answer 1

sql.add(' and GGLC like :GGLC and LB like :LB and GLZT like :GLZT and CDMC like :CDMC and UNIT like :TUNIT and SX like :SX');
改为
sql.add(' and isnull(GGLC,"") like :GGLC and isnull(LB,"") like :LB and isnull(GLZT,"") like :GLZT and isnull(CDMC,"") like :CDMC and isnull(UNIT,"") like :TUNIT and isnull(SX,"") like :SX');

Answer 2

procedure TForm19.Button3Click(Sender: TObject);
var YBXH,WH,YBMC,QH,CDMC,......:string;
begin
YBXH:='%';WH:='%';QH:='%';CDMC:='%';TUNIT:='%';YBMC:='%';
......
if CheckBox1.Checked=true then YBXH:=YBXH+trim(edit3.Text);
if CheckBox2.Checked=true then WH:=WH+trim(edit27.Text);
if CheckBox3.Checked=true then YBMC:=YBMC+trim(wwDBLookupCombo5.text);
......
WITH wwQuery1 DO
begin
close;
sql.clear;
sql.Add('select * from ybtz ');
sql.add('where YBXH like :YBXH and WH like :WH and YBMC like :YBMC and QH like :QH ');
sql.add(' and GGLC like :GGLC and LB like :LB and GLZT like :GLZT and CDMC like :CDMC and UNIT like :TUNIT and SX like :SX');
sql.Add('order by WH,YBMC');
paramByName('YBXH').asstring:=YBXH+'%';
paramByName('WH').asstring:=WH+'%';
......
open;
end;

Answer 3

procedure TForm1.Button1Click(Sender: TObject);
begin
case RadioGroup1.ItemIndex of
0:
begin
adoquery1.Close;
adoquery1.SQL.Clear;
adoquery1.SQL.Add('select * from 表 where 字段 like '+''''+trim(edit1.Text)+'''');
end;
1: //同理

end;

end;

Answer 4

adoquery1.Close;
adoquery1.SQL.Clear;
adoquery1.SQL.Add('select * from 表 where 字段 like %'+edit1.text+'%');