Output in a comma list

Question

Hi all,
i am need the change the output of the below query.
SQL> select department_id,employee_id from employees order by department_id;
DEPARTMENT_ID EMPLOYEE_ID
           10         200
           20         201
           20         202
           30         114
           30         119
           30         115
           30         116
           30         117
           30         118
           40         203
           50         198
DEPARTMENT_ID EMPLOYEE_ID
           50         199
           50         120
           50         121
           50         122
           50         123
           50         124
           50         125
           50         126
           50         127
           50         128
           50         129
DEPARTMENT_ID EMPLOYEE_ID
           50         130
           50         131
           50         132
           50         133
           50         134
           50         135
           50         136
           50         137
           50         138
           50         139
           50         140
DEPARTMENT_ID EMPLOYEE_ID
           50         141
           50         142
           50         143
           50         144
           50         180
           50         181
           50         182
           50         183
           50         184
           50         185
           50         186
DEPARTMENT_ID EMPLOYEE_ID
           50         187
           50         188
           50         189
           50         190
           50         191
           50         192
           50         193
           50         194
           50         195
           50         196
           50         197
DEPARTMENT_ID EMPLOYEE_ID
           60         104
           60         103
           60         107
           60         106
           60         105
           70         204
           80         176
           80         177
           80         179
           80         175
           80         174
DEPARTMENT_ID EMPLOYEE_ID
           80         173
           80         172
           80         171
           80         170
           80         169
           80         168
           80         145
           80         146
           80         147
           80         148
           80         149
DEPARTMENT_ID EMPLOYEE_ID
           80         150
           80         151
           80         152
           80         153
           80         154
           80         155
           80         156
           80         157
           80         158
           80         159
           80         160
DEPARTMENT_ID EMPLOYEE_ID
           80         161
           80         162
           80         163
           80         164
           80         165
           80         166
           80         167
           90         101
           90         100
           90         102
          100         110
DEPARTMENT_ID EMPLOYEE_ID
          100         108
          100         111
          100         112
          100         113
          100         109
          110         206
          110         205
                      178
107 rows selected.Now i need to change this output in the floowing manner.
DEPARTMENT_ID EMPLOYEE_ID
           10         200
           20         201,202
           30         114,119,115,116,117,118
           30         119
           40         203
the employee id should be in a comma separated list instead of a single row.

Answer 1

rajavu1 wrote:
You can use Sys_Connect_By_path also as given below.
SQL> SELECT DEPTNO,
2 LTRIM(MAX(SYS_CONNECT_BY_PATH(EMPNO,',')),',')  AS EMPNOLIST
3 FROM   (SELECT deptno,
4                         EMPNO,
5                         ROW_NUMBER() OVER (PARTITION BY DEPTNO ORDER BY EMPNO) AS CURR,
6                         ROW_NUMBER() OVER (PARTITION BY deptno ORDER BY empno) -1 AS prev
7               FROM   emp)
8  GROUP BY deptno
9  CONNECT BY PREV = PRIOR CURR AND DEPTNO = PRIOR DEPTNO
10  START WITH curr = 1;
DEPTNO EMPNOLIST
30 7499,7521,7654,7698,7844,7900
20 7369,7566,7876,7902
10 7782,7839
SQL>
Urgh! Misuse of MAX and GROUP BY in a hierarchical query, and an unnecessary extra row_number calculation.
SQL> ed
Wrote file afiedt.buf
  1  select deptno
  2        ,trim(',' from sys_connect_by_path(empno,',')) as empnolist
  3  from  (select deptno
  4               ,empno
  5               ,row_number() over (partition by deptno order by empno) as rn
  6         from emp)
  7  where connect_by_isleaf = 1
  8  connect by deptno = prior deptno and rn = prior rn + 1
  9* start with rn = 1
SQL> /
    DEPTNO EMPNOLIST
        10 7782,7839,7934
        20 7369,7566,7788,7876,7902
        30 7499,7521,7654,7698,7844,7900In 10g you can use CONNECT_BY_ISLEAF to give only the leaf nodes of the hierarchy, and when comparing row numbers it's easier to just "+1" to the prior in the connect by clause rather than calculating an extra row_number value.