我做了一个for语句,从中取出
Var
IntGradeID: Integer;
Begin
...
IntGradeID := qryGrade.FieldByNames("GradeID").AsInteger;
...
//下面为出错行,提示:IntGradeID不是有效的列名
SQL.Add("Select * From cClass Where GradeID=IntGradeID")
...
End;烦请帮忙,谢谢!
Var
IntGradeID: Integer;
Begin
...
IntGradeID := qryGrade.FieldByNames("GradeID").AsInteger;
...
//下面为出错行,提示:IntGradeID不是有效的列名
SQL.Add("Select * From cClass Where GradeID=IntGradeID")
...
End;烦请帮忙,谢谢!
SQL.Add('Select * From cClass Where GradeID='''+IntToStr(IntGradeID)+'''')
SQL.Add('Select * From cClass Where GradeID='+IntToStr(IntGradeID))
IntGradeID: Integer;
Begin
...
IntGradeID := qryGrade.FieldByNames("GradeID").AsInteger;
...
//下面为出错行,提示:IntGradeID不是有效的列名
SQL.Add("Select * From cClass Where GradeID=IntGradeID")
...
End;也可写为:Var
IntGradeID: Integer;
Begin
...
IntGradeID := qryGrade.FieldByNames("GradeID").AsString;
...
//下面为出错行,提示:IntGradeID不是有效的列名
SQL.Add("Select * From cClass Where GradeID= ' + intGradeID")
...
End;
能解释一下加单引号,双引号的区别吗?
除非是字符串
IntGradeID: Integer;
Begin
...
IntGradeID := qryGrade.FieldByNames('GradeID').AsInteger;
...
SQL.Add('Select * From cClass Where GradeID= '+ IntToStr(IntGradeID)+'')
...
End;