How to convert rows to columns in Oracle SQL

问题

For a requirement I have to create a query to show Employees Schedule per week. Query is like this:

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

Output of this query is like:

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

I want the output in below format:

1   7.6  7.6   7.6   7.6   7.6   OFF  OFF

How to achieve it?

回答1:

If you are OK with concatenated list, then use LISTAGG which was introduced in Oracle 11g Release 2.

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;

For example,

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>