如何在 Oracle SQL 中将行转换为列

Question

对于要求，我必须创建一个查询来显示每周的员工时间表。查询是这样的：

select weekday, sched_hrs
  from table
 where emplid = '12345'
   and weekday_name= 1

此查询的输出如下：

Weekday |  Sched_hrs
-------------------- 
   1    |    7.6
   1    |    7.6
   1    |    7.6
   1    |    7.6
   1    |    7.6
   1    |    OFF
   1    |    OFF

我想要以下格式的输出：

1   7.6  7.6   7.6   7.6   7.6   OFF  OFF

如何实现？

Answer 1

如果您同意串联列表，请使用Oracle 11g Release 2中介绍的

LISTAGG

。

SELECT weekday, LISTAGG(Sched_hrs, ',') WITHIN GROUP (ORDER BY weekday) AS Sched_hrs
FROM   table 
 WHERE emplid = '12345' AND weekday_name= 1
GROUP BY weekday;

例如，

SQL> column employees format a50
SQL> SELECT deptno, LISTAGG(ename, ',') WITHIN GROUP (ORDER BY ename) AS employees
  2  FROM   emp
  3  GROUP BY deptno;

    DEPTNO EMPLOYEES
---------- --------------------------------------------------
        10 CLARK,KING,MILLER
        20 ADAMS,FORD,JONES,SCOTT,SMITH
        30 ALLEN,BLAKE,JAMES,MARTIN,TURNER,WARD

SQL>

Answer 2

在11g中您可以使用PIVOT功能。 请参阅文档：

http://www.oracle.com/technetwork/articles/sql/11g-pivot-097235.html