SQL Rows concatenation based on single column

I have Table with values

X     Y     Z  
-     ---   - 
1     abc   P
1     def   Q

I need a normal query (not pl/sql) which开发者_运维知识库 can give result as

X  Y        Z
-  -------  ---
1  abc,def  P,Q

i.e Based on column X the values are converted into csv format

There can be more than three columns.

You can choose any one of the following techniques to aggregate your strings

On occasion it is necessary to aggregate data from a number of rows into a single row, giving a list of data associated with a specific value. Using the SCOTT.EMP table as an example, we might want to retrieve a list of employees for each department. Below is a list of the base data and the type of output we would like to return from an aggregate query.

Base Data:

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

Desired Output:

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

Personally, I find this syntax very readable

SELECT x, wm_concat(y), wm_concat(z) 
FROM   xyz
GROUP BY x;

For Postgre you could use something like

select X, array_to_string(array_accum(Y), ',') as Y, array_to_string(array_accum(Z), ',') as Z
from Table
group by X

It's array_to_string and array_accum are built-in functions.