with adoquery1 do begin close; sql.clear; sql.add('select a.*,b.* from tableA a left join tableB b on a.id=b.id '); open; end;datasource1.dataset:=adoquery1; dbdrid1.datasource:=datasource1;
with adoquery1 do begin close; sql.clear; sql.add('select a.*,b.* from a,b where a.id=b.id'); open; end;
with adoquery1 do begin close; sql.clear; sql.add('select a.*,b.* from a,b where a.id=b.id'); open; end;
begin
close;
sql.clear;
sql.add('select a.*,b.* from tableA a left join tableB b on a.id=b.id ');
open;
end;datasource1.dataset:=adoquery1;
dbdrid1.datasource:=datasource1;
begin
close;
sql.clear;
sql.add('select a.*,b.* from a,b where a.id=b.id');
open;
end;
begin
close;
sql.clear;
sql.add('select a.*,b.* from a,b where a.id=b.id');
open;
end;
在不同的时刻,在sql中写入不同的SQL语句
这样就可以实现不同要求的查询并得到不同的结果显示在dbgrid 中