大家好:
我在程序中想判断一个整数是否为空,我的表为空,但用下边的程序却得不出为空的结果:
代码如下:
var
d1:integer;
begin
query1.close;
query1.sql.clear;
query1.sql.text:='select * from datexu';
query1.prepare;
query1.open;
d1:=query1.fields[1].asinteger;
if d1=null then
showmessage('为空.');
end;
望大家指教,谢谢!
王振亚
2003.09.18
我在程序中想判断一个整数是否为空,我的表为空,但用下边的程序却得不出为空的结果:
代码如下:
var
d1:integer;
begin
query1.close;
query1.sql.clear;
query1.sql.text:='select * from datexu';
query1.prepare;
query1.open;
d1:=query1.fields[1].asinteger;
if d1=null then
showmessage('为空.');
end;
望大家指教,谢谢!
王振亚
2003.09.18
if d1=0 then
d1:String ;
begin
query1.close;
query1.sql.clear;
query1.sql.text:='select * from datexu';
query1.prepare;
query1.open;
d1:=query1.fields[1].AsString;
if Trim(d1)='' then
showmessage('为空.');
end;
if Query1.Fields[1].IsNull then
query1.close;
query1.sql.clear;
query1.sql.text:='select * from datexu';
query1.prepare;
query1.open;
if VarIsNull(query1.fields[1].value) then
showmessage('为空.');
end;
showmessage('为空.');
query1.close;
query1.sql.clear;
query1.sql.text:='select * from datexu';
query1.prepare;
query1.open;
if query1.fields[1].value is null then
showmessage('为空.');
end;