declare @A table
( id nvarchar(8), [no] nvarchar(8), a_string1 nvarchar(8), a_string2 nvarchar(8) );
insert into @A values('0001','0001','','');
insert into @A values('0001','0002','','');
insert into @A values('0001','0003','','');
insert into @A values('0001','0004','','');
insert into @A values('0001','0001','1111','1111');
insert into @A values('0001','0002','1111','1111');
insert into @A values('0001','0003','1111','1111');
insert into @A values('0001','0004','1111','1111');
表A,前面两个字段相同的数据有两条,那么只取其中的一条,这样的查询语句要怎么写,后面两个字段的内容不止空或者1111两种情况?