求教进出库的问题

Question

数据表结构
--------------------------------------------
number              type             t_id
--------------------------------------------
54                   1                 12
30                   2                 13
68                   1                 13
---------------------------------------------type中 1代表 进了多少，2代表出了多少 现在想要实现的结果如下：
---------------------------------------------
t_id            进                     出           
--------------------------------------------
12              54                 0
13              68                 30
--------------------------------------------------
求解

Answer 1

SQL> select * from test;         N          T         ID
---------- ---------- ----------
        54          1         12
        30          2         13
        68          1         13SQL> select id,sum(n * decode(t,1,1,0)) as "in",
  2          sum(n * decode(t,2,1,0)) as "out"
  3  from test group by id;        ID         in        out
---------- ---------- ----------
        13         68         30
        12         54          0SQL>