company表结构如下:
ID area
1 A
2 A
3 B
4 A
5 E
6 F
select * from company where area = 'A';
结果如下:
ID area
1 A
2 A
4 A
现在我想得到所有的结果,也想用类似select * from company where area = 'A'结构的语句来实现
注意:不能使用like,也不能用select * from company实现
ID area
1 A
2 A
3 B
4 A
5 E
6 F
select * from company where area = 'A';
结果如下:
ID area
1 A
2 A
4 A
select * from company where area = '';
理想的结果如下:
ID area
1 A
2 A
3 B
4 A
5 E
6 F
ID area
1 A
2 A
3 B
4 A
5 E
6 F
select * from company where area = 'A';
结果如下:
ID area
1 A
2 A
4 A
现在我想得到所有的结果,也想用类似select * from company where area = 'A'结构的语句来实现
注意:不能使用like,也不能用select * from company实现
ID area
1 A
2 A
3 B
4 A
5 E
6 F
select * from company where area = 'A';
结果如下:
ID area
1 A
2 A
4 A
select * from company where area = '';
理想的结果如下:
ID area
1 A
2 A
3 B
4 A
5 E
6 F
select * from company where area = area;
或
select * from company where 1=1
select * from company where area like '%';
这样当area='A'时结果如下:
ID area
1 A
2 A
4 A
当area=''时查询出所有结果
我现在不需要模糊查询,能否用一条语句就实现这个功能?
1. open 所有記錄 ( select * from tabnemae ') 2. 過瀘全部記錄
with adoquery1 do
begin
filtered:=false;
filter:='';
filtered:=true;
end; 3: with adoquery1 do //過濾為A的記錄
begin
filtered:=false;
filter:=format('area =''%s''',['A']);
filtered:=true;
end;
你看這個是不是你想要的?因為你說的不太明白