日期:2014-05-17 浏览次数:20834 次
create table test (a number)
select nvl(a,0) from test
hr@ORCL> create table test (a number);
Table created.
hr@ORCL> select nvl(a,0) from test;
no rows selected
hr@ORCL> insert into test values(NULL);
1 row created.
hr@ORCL> select nvl(a,0) from test;
NVL(A,0)
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0