Oracle Pivot 行到列模式匹配

Question

我想将行重新排列成列（在下面的 tbl2 中）以计算 EXEN col 的 EXEN 出现次数，以及 MPACODE 列以 MPA 开头的任何代码的出现次数。

SELECT *
FROM   (select code from tbl2 where pidm='4062161')
PIVOT  (count(*) FOR (code) IN ('EXEN' AS EXEN, 'MPA%' AS MPACODE));

tbl2:

期望的输出：

实际输出：

Answer 1

您必须执行一个中间步骤将所有 MPA% 转换为 MPA 请参阅子查询 dt2

with dt as (
select 'EXEN' code from dual union all
select 'MPA'||rownum from dual connect by level <= 10),
dt2 as (
select 
case when code like 'MPA%' then 'MPA' else code end as code
from dt)
select *
from dt2
pivot (
count(*) for
(code) IN ('EXEN' AS EXEN, 'MPA' AS MPACODE));

      EXEN    MPACODE
---------- ----------
         1         10

PIVOT 执行相等比较（不是 LIKE），因此这是无效的：'MPA%' AS MPACODE 和原因查询失败的原因。

Answer 2

例如：

  select
   count(case when code='EXEN' then 1 end) exen,
   count(case when code like 'MPA%' then 1 end) mpacode
     from  tbl2 where pidm='4062161';

Oracle Pivot 行到列模式匹配

Oracle Pivot rows to columns pattern matching

sql

oracle

pivot