Oracle 定义变量
--这是我在SQL 2005中写的SQL：create table #tb(id int,tname nvarchar(10))insert into #tb select 1,'x' union all select 2,'y'begindeclare @i intselect @i = count(1) from #tb where id=1 and tname='a'if @i = 0 begin insert into #tb values (1,'a'); update #tb set tname='aa' where id=1 and tname='a' endselect @i = count(1) from #tb where id=2 and tname='y'if @i=0 begin insert into #tb values (2,'y'); update #tb set tname='yy' where id=1 and tname='y' endselect @i = count(1) from #tb where id=1 and tname='c'if @i = 0 begin insert into #tb values (1,'c'); update #tb set tname='cc' where id=1 and tname='c' endendselect * from #tb
