首先让我们来看看这个神奇的函数wm_concat(列名),该函数可以把列值以","号分隔起来,并显示成一行,接下来上例子,看看这个神奇的函数如何应用
准备测试数据
SQL> create table test(id number,name varchar2(20));
SQL> insert into test values(1,'a');
SQL> insert into test values(1,'b');
SQL> insert into test values(1,'c');
SQL> insert into test values(2,'d');
SQL> insert into test values(2,'e');
SQL> commit;
效果1 : 行转列
SQL> select wm_concat(name) from test;
WM_CONCAT(NAME)
-------------------------------------------------------------------------
a,b,c,d,e
效果2: 把结果里的逗号替换成"|"
SQL> select replace(wm_concat(name),',','|') from test;
REPLACE(WM_CONCAT(NAME),',','|')
-----------------------------------------------------------------------
a|b|c|d|e
效果 3:按ID分组合并name
SQL> select id,wm_concat(name) name from test group by id;
ID NAME
---------- ------------------------------
1 a,b,c
2 d,e