SYS_CONNECT_BY_PATH with CLOB - sql

Question

I have an ORA-01489: result of string concatenation is too long error executing this query on a Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production, PL/SQL Release 11.2.0.4.0 - Production, CORE 11.2.0.4.0 Production, TNS for Linux: Version 11.2.0.4.0 - Production, NLSRTL Version 11.2.0.4.0 - Production:
SELECT "USER_PRIMARY_UNIT","LOGIN","FIRST_NAME","LAST_NAME","UNIT_ROLE"
FROM (
SELECT user_primary_unit,login, first_name, last_name,
LTRIM(MAX(SYS_CONNECT_BY_PATH(rights,' / '))
KEEP (DENSE_RANK LAST ORDER BY curr),' / ') AS UNIT_ROLE
FROM
(SELECT login,
first_name,
last_name,
user_primary_unit,
rights,
ROW_NUMBER() OVER (PARTITION BY login ORDER BY rights) AS curr,
ROW_NUMBER() OVER (PARTITION BY login ORDER BY rights) -1 AS prev
FROM (select member0_.login, member0_.first_name first_name, unit2.unit_name user_primary_unit, member0_.last_name last_name,
CONCAT(CONCAT(unit.unit_name, ' - '), role3_.role_name) rights
from
IOT_DEVICES.t_member member0_
inner join IOT_DEVICES.t_user member0_1_ on member0_.member_id=member0_1_.user_id
inner join IOT_DEVICES.t_playable_role playedrole1_ on member0_.member_id=playedrole1_.user_id
inner join IOT_DEVICES.t_unit_role unitrole2_ on playedrole1_.unit_role_id=unitrole2_.unit_role_id
inner join IOT_DEVICES.t_role role3_ on unitrole2_.role_id=role3_.role_id
inner join IOT_DEVICES.t_unit unit on unitrole2_.unit_id=unit.unit_id
inner join IOT_DEVICES.t_unit unit2 on unit2.unit_id=member0_1_.primary_unit_id
where current_date between playedrole1_.start_date and playedrole1_.end_date
order by unit.unit_name
))
GROUP BY login, first_name, last_name, user_primary_unit
CONNECT BY prev = PRIOR curr AND login = PRIOR login
START WITH curr = 1
)
ORDER BY user_PRIMARY_UNIT, FIRST_NAME, LAST_NAME;
The problem with this query is with the use of CONCAT operator (||). Concat operator returns char1 concatenated with char2. The string returned is in the same character set as char1. So here concat operator is trying to return varchar2, which has limit of 4000 characters and getting exceeded. This problem may also come when we try to CONCAT a VARCHAR2 with CLOB. So here I want simply convert its first string to CLOB and avoid this error. After converting first string to CLOB, CONCAT operator will return string of CLOB type
So I add the TO_CLOB to convert the types but then I have the next error:
ORA-00932: inconsistent datatypes: expected - got CLOB
SELECT "USER_PRIMARY_UNIT","LOGIN","FIRST_NAME","LAST_NAME","UNIT_ROLE"
FROM (
SELECT user_primary_unit,login, first_name, last_name,
LTRIM(MAX(SYS_CONNECT_BY_PATH(rights,' / '))
KEEP (DENSE_RANK LAST ORDER BY curr),' / ') AS UNIT_ROLE
FROM
(SELECT login,
first_name,
last_name,
user_primary_unit,
rights,
ROW_NUMBER() OVER (PARTITION BY login ORDER BY rights) AS curr,
ROW_NUMBER() OVER (PARTITION BY login ORDER BY rights) -1 AS prev
FROM (select member0_.login, member0_.first_name first_name, unit2.unit_name user_primary_unit, member0_.last_name last_name,
TO_CLOB(CONCAT(CONCAT(unit.unit_name, ' - '), role3_.role_name)) rights
from
IOT_DEVICES.t_member member0_
inner join IOT_DEVICES.t_user member0_1_ on member0_.member_id=member0_1_.user_id
inner join IOT_DEVICES.t_playable_role playedrole1_ on member0_.member_id=playedrole1_.user_id
inner join IOT_DEVICES.t_unit_role unitrole2_ on playedrole1_.unit_role_id=unitrole2_.unit_role_id
inner join IOT_DEVICES.t_role role3_ on unitrole2_.role_id=role3_.role_id
inner join IOT_DEVICES.t_unit unit on unitrole2_.unit_id=unit.unit_id
inner join IOT_DEVICES.t_unit unit2 on unit2.unit_id=member0_1_.primary_unit_id
where current_date between playedrole1_.start_date and playedrole1_.end_date
order by unit.unit_name
))
GROUP BY login, first_name, last_name, user_primary_unit
CONNECT BY prev = PRIOR curr AND login = PRIOR login
START WITH curr = 1
)
ORDER BY user_PRIMARY_UNIT, FIRST_NAME, LAST_NAME;
I also tried to use the package Hierarchy defined Here but then I got a ORA-00932: inconsistent datatypes: expected - got CLOB
https://community.oracle.com/thread/965324?start=0&tstart=0
SELECT "USER_PRIMARY_UNIT","LOGIN","FIRST_NAME","LAST_NAME","UNIT_ROLE"
FROM (
SELECT user_primary_unit,login, first_name, last_name,
LTRIM(MAX(hierarchy.branch(level,rights,' / '))
KEEP (DENSE_RANK LAST ORDER BY curr),' / ') AS UNIT_ROLE
FROM
(SELECT login,
first_name,
last_name,
user_primary_unit,
rights,
ROW_NUMBER() OVER (PARTITION BY login ORDER BY rights) AS curr,
ROW_NUMBER() OVER (PARTITION BY login ORDER BY rights) -1 AS prev
FROM (select member0_.login, member0_.first_name first_name, unit2.unit_name user_primary_unit, member0_.last_name last_name,
TO_CLOB(CONCAT(CONCAT(unit.unit_name, ' - '), role3_.role_name)) rights
from
IOT_DEVICES.t_member member0_
inner join IOT_DEVICES.t_user member0_1_ on member0_.member_id=member0_1_.user_id
inner join IOT_DEVICES.t_playable_role playedrole1_ on member0_.member_id=playedrole1_.user_id
inner join IOT_DEVICES.t_unit_role unitrole2_ on playedrole1_.unit_role_id=unitrole2_.unit_role_id
inner join IOT_DEVICES.t_role role3_ on unitrole2_.role_id=role3_.role_id
inner join IOT_DEVICES.t_unit unit on unitrole2_.unit_id=unit.unit_id
inner join IOT_DEVICES.t_unit unit2 on unit2.unit_id=member0_1_.primary_unit_id
where current_date between playedrole1_.start_date and playedrole1_.end_date
order by unit.unit_name
))
GROUP BY login, first_name, last_name, user_primary_unit
CONNECT BY prev = PRIOR curr AND login = PRIOR login
START WITH curr = 1
)
ORDER BY user_PRIMARY_UNIT, FIRST_NAME, LAST_NAME;
Then I tried as well with sys.stragg , but i got a ORA-00978: nested group function without GROUP BY
SELECT "USER_PRIMARY_UNIT","LOGIN","FIRST_NAME","LAST_NAME","UNIT_ROLE"
FROM (
SELECT user_primary_unit,login, first_name, last_name,
LTRIM(MAX(SYS_CONNECT_BY_PATH(rights,' / '))
KEEP (DENSE_RANK LAST ORDER BY curr),' / ') AS UNIT_ROLE
FROM
(SELECT login,
first_name,
last_name,
user_primary_unit,
rights,
ROW_NUMBER() OVER (PARTITION BY login ORDER BY rights) AS curr,
ROW_NUMBER() OVER (PARTITION BY login ORDER BY rights) -1 AS prev
FROM (select member0_.login, member0_.first_name first_name, unit2.unit_name user_primary_unit, member0_.last_name last_name,
sys.stragg(sys.stragg(unit.unit_name || ' - ' || role3_.role_name)) rights
from
IOT_DEVICES.t_member member0_
inner join IOT_DEVICES.t_user member0_1_ on member0_.member_id=member0_1_.user_id
inner join IOT_DEVICES.t_playable_role playedrole1_ on member0_.member_id=playedrole1_.user_id
inner join IOT_DEVICES.t_unit_role unitrole2_ on playedrole1_.unit_role_id=unitrole2_.unit_role_id
inner join IOT_DEVICES.t_role role3_ on unitrole2_.role_id=role3_.role_id
inner join IOT_DEVICES.t_unit unit on unitrole2_.unit_id=unit.unit_id
inner join IOT_DEVICES.t_unit unit2 on unit2.unit_id=member0_1_.primary_unit_id
where current_date between playedrole1_.start_date and playedrole1_.end_date
order by unit.unit_name
))
GROUP BY login, first_name, last_name, user_primary_unit
CONNECT BY prev = PRIOR curr AND login = PRIOR login
START WITH curr = 1
)
ORDER BY user_PRIMARY_UNIT, FIRST_NAME, LAST_NAME;

Answer 1

You can build hierarchy CLOB path with subquery factoring syntax This may run really slow. Consider having two path columns - one for varchar2 result and one for CLOB. Build varchar2 till size allows, and keep NULL in CLOB path, and switch to CLOB when out of varchar2 capacity. This is a different question though.
with
base as (
select
level as id,
case when level > 1 then level - 1 end as parent_id,
dbms_random.string('X', 2000) as val
from dual
connect by level <= 50
),
hier(id, parent_id, val, path) as (
select
b.id,
b.parent_id,
b.val,
to_clob(concat('/', b.val)) as path
from base b
where b.parent_id is null
union all
select
b.id,
b.parent_id,
b.val,
concat(h.path, to_clob(' / '||b.val) )
from base b
join hier h on h.id = b.parent_id
)
select rownum, length(h.path)
from hier h;
ROWNUM LENGTH(H.PATH)
1 2001
2 4004
3 6007
4 8010
5 10013
6 12016
7 14019
8 16022
9 18025
10 20028
11 22031
12 24034
13 26037
14 28040
15 30043
16 32046
17 34049
18 36052
19 38055
20 40058
21 42061
22 44064
23 46067
24 48070
25 50073
26 52076
27 54079
28 56082
29 58085
30 60088
31 62091
32 64094
33 66097
34 68100
35 70103
36 72106
37 74109
38 76112
39 78115
40 80118
41 82121
42 84124
43 86127
44 88130
45 90133
46 92136
47 94139
48 96142
49 98145
50 100148

Answer 2

You might found this page, because you're trying to aggregate strings longer than 4000 characters and remembered the different techniques.
If so, I created a small example, based on #B Samedi's answer to help you out, when you're not able to use user defined aggregates
with dummy_text as (
select 'teststring ' || rownum str from dual connect by rownum < 2
)
, indexed_strings as (
select str, row_number() over (order by 'x') rn, ',' separator from dummy_text
)
, hier (str, lvl) as (
select to_clob(i.str), rn from indexed_strings i where rn = (select max(rn) from indexed_strings)
union all
select concat(to_clob(concat(i.str, i.separator)), h.str), h.lvl - 1 from indexed_strings i join hier h on h.lvl - 1 = i.rn
)
select str from hier where lvl = 1