create table testTable ( id number, name varchar2(100) ) select * from testTable insert into testTable(id,name) values(1,‘user1‘) insert into testTable(id,name) values(2,‘‘) insert into testTable(id,name) values(3,null) select count(id) from testTable t where t.name=‘‘ select count(id) from testTable t where t.name is null or t.name!=‘‘ select id,nvl(name,‘null‘) from testTable select id,nullif(name,‘1231231‘) from testTable drop table testTable
时间: 2024-12-28 23:05:59