oracle判斷某字段是否為空

1、sql語句中判斷非空不能用等號，因為null是特殊字符，必須使用關鍵字is和not

2、測試數據

a、測試數據

create table atest(
aid varchar2(6),
aname varchar2(50)
)

insert into atest values('1','a');
insert into atest values('2','b');
insert into atest values('3','');
insert into atest values('4','');
insert into atest values('21','');
insert into atest values('22','');
insert into atest values('31','');
insert into atest values('','');

 

 b、判斷是否為空

select * from atest where aname is null;

 

 

c、判斷不為空

select * from atest where aname is not null;