The document discusses various ways to concatenate or aggregate column values in Oracle databases. Older methods like XMLAGG, CONNECT BY, and custom aggregate functions are compared to the simpler LISTAGG function available in Oracle 11g and higher. Upgrading to newer database versions brings improved developer productivity through easier string aggregation queries.

1. 1
Connor McDonald
bit.ly/techguysong

2. Copyright © 2018, Oracle and/or its affiliates. All rights reserved. |
The latest and greatest

3. The latest and greatest
Copyright © 2019 Oracle and/or its affiliates.

4. design.oracle.com

5. Copyright © 2019 Oracle and/or its affiliates.

7. 9
Me
youtube bit.ly/youtube-connor
blog connor-mcdonald.com
twitter @connor_mc_d
400+ posts mainly on database & development
250 technical videos, new uploads every week
rants and raves on tech and the world :-)

8. 10
etc...
facebook bit.ly/facebook-connor
linkedin bit.ly/linkedin-connor
instagram bit.ly/instagram-connor
slideshare bit.ly/slideshare-connor

9. 11
missed OpenWorld ?
http://bit.ly/oow19mega

10. "latest and greatest"
Copyright © 2019 Oracle and/or its affiliates.

11. 15
18c, 19c, 20c

12. The following is intended to outline our general product direction. It is intended for information purposes
only, and may not be incorporated into any contract. It is not a commitment to deliver any material, code,
or functionality, and should not be relied upon in making purchasing decisions. The development,
release, timing, and pricing of any features or functionality described for Oracle’s products may change
and remains at the sole discretion of Oracle Corporation.
Statements in this presentation relating to Oracle’s future plans, expectations, beliefs, intentions and
prospects are “forward-looking statements” and are subject to material risks and uncertainties. A detailed
discussion of these factors and other risks that affect our business is contained in Oracle’s Securities and
Exchange Commission (SEC) filings, including our most recent reports on Form 10-K and Form 10-Q
under the heading “Risk Factors.” These filings are available on the SEC’s website or on Oracle’s website
at http://www.oracle.com/investor. All information in this presentation is current as of September 2019
and Oracle undertakes no duty to update any statement in light of new information or future events.
Safe Harbor
Copyright © 2019 Oracle and/or its affiliates.

13. 17
before we begin

14. 18
let's clear the air

15. 19
it's probably not about features

17. 21
upgrade

18. STOP

19. FREAKIN'

20. THE

21. HELL

22. OUT :-)

23. 27
18c
19c
20c
21c
etc

24. 28
"Upgrade
every single
year !?!?!?!?!?!?"

25. 29
no

26. 30
customer needs/types

27. 31
W T H

28. 32
"I need security patches
but other than that,
leave me alone..."

29. 2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
EXTENDED*
18c
11.2.0.4 EXTENDED
EXTENDED12.1.0.2
12.2.0.1
19c
Paid Extended SupportPremier Waived Extended Support Fee
MOS Note 742060.1

30. • Premier Support to 2023
• Extended Support to 2026

31. 12.2.0.1
12.1.0.2
11.2.0.4
12.2.0.2
12.2.0.3

32. 36
check out autoupgrade
https://mikedietrichde.com/2019/04/29/the-new-autoupgrade-utility-in-
oracle-19c/

33. 37
W T H

34. 38
O M G

35. 39
"OMG! OMG! OMG! OMG!
Competive edge!
Fix to killer issue!
Let's upgrade right now!"

36. 2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
EXTENDED*
18c
11.2.0.4 EXTENDED
EXTENDED12.1.0.2
12.2.0.1
19c
20c
21c
22c
*Estimated Release

37. 41
database granularity

38. 42
11.2.0.4 => 12.1 => 12.1.0.2 => 12.2
11.2.0.4 => 12.2 => 19c

40. 44
this session

41. 45
preparing for when you get there

42. 46
there's a lot in 18, 19 .... and 20

43. 47
get started right now

44. 48
install nothing

45. https://cloud.oracle.com/tryit

46. 50
install a little bit

47. https://bit.ly/oraprebuilt

48. 52
install lots :-)

49. http://bit.ly/download19c

50. 54
18c/19c install lots :-)

52. 56
18c/19c install lots :-)

54. 59
install lots :-)

55. 61
1) read-only ORACLE_HOME

56. 62
2) database in Docker

58. UNZIP
INSTALL
RPM INSTALL
DOCKER
READ-ONLY

59. 65
vmware

62. 68
Doc ID 249212.1

63. run, lift & shift, license

65. 71
global temporary tablesprivate

66. 72
SQL server etc

67. 73
read locking

68. 74
SELECT empno, ename, job
INTO #HighPaidJobs
FROM emp
WHERE sal > 3000

69. 75
migration to Oracle difficult

70. SQL> create private temporary table ORA$PTT_MY_TT
2 ( empno int , ename varchar2(20)) ;
Table created.
SQL> insert into ORA$PTT_MY_TT
2 select empno, ename
3 from scott.emp
4 where sal > 3000;
1 row created.
SQL> select * from ORA$PTT_MY_TT;
EMPNO ENAME
---------- --------------------
7839 KING

71. 77
"um...looks the same as before"

72. 78
SQL> commit;
Commit complete.
SQL> select * from ORA$PTT_MY_TT;
select * from ORA$PTT_MY_TT
*
ERROR at line 1:
ORA-00942: table or view does not exist

73. 79
it's really temporary

74. SQL> create private temporary table ORA$PTT_MY_TT
2 ( empno int , ename varchar2(20)) ;
Table created.
SQL> select *
2 from user_tables
3 where table_name = 'ORA$PTT_MY_TT' ;
no rows selected
SQL> select *
2 from all_objects
3 where object_name = 'ORA$PTT_MY_TT' ;
no rows selected

75. 82
it's really private

76. 83
SQL> create private temporary table ORA$PTT_MY_TT
2 ( empno int ,
3 ename varchar2(20)) ;
Table created.
SQL> create private temporary table ORA$PTT_MY_TT
2 ( deptno int ,
3 dname varchar2(20),
4 bonus int,
5 logo blob) ;
Table created.

77. 84
it's all in the name !

78. SQL> create private temporary table MY_TT ( x int ) ;
ERROR at line 1:
ORA-00903: invalid table name
SQL> show parameter private
NAME TYPE VALUE
------------------------------- ----------- -----------
private_temp_table_prefix string ORA$PTT_

80. 87
remember temporary undo?

81. SQL> insert into t values ('Hello','There');
insert into t values ('Hello','There')
*
ERROR at line 1:
ORA-16000: database open for read-only access

82. 89
Active Data Guard

83. SQL> alter session set temp_undo_enabled=true;
Session altered.
SQL> create global temporary table GTT_REPORT_STAGING
2 ( ... );
SQL> insert into GTT_REPORT_STAGING
2 select ...
SQL> select * from GTT_REPORT_STAGING join FIN_RESULTS
2 ...

84. 91
100%
% of people that
found this useful

85. 92
19c

86. 93
DML redirect

87. Standby Primary
SQL> insert into REPORTING_STAGING
2 select * from ...

88. 95
bonus DataGuard

89. 96
we've all done this :-)

90. 97
Standby Primary

91. 98
18c

92. RMAN> connect target sys/oracle@MY_STANDBY
RMAN> connect auxiliary sys/oracle@MY_PRIMARY
RMAN> recover database from service PRIMARY;
Starting recover at 12.10.2018 14:05:17
using target database control file instead of recovery catalog
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=187 device type=DISK
...
...

93. 100
bonus bonus DataGuard !

94. 101
SQL> alter database force logging;

96. 103
18c

97. 104
SQL> alter database set standby nologging for data availability;
deferred commit

98. 105
SQL> alter database set standby nologging for load performance;
deferred transmission

100. 107
a nice form of murder :-)

101. 108
aka, #1 reason for upgrading to 18c

102. 109
SQL> insert into MY_TABLE
2 select *
3 from MY_HUGE_GREAT_FAT_TABLE;

104. 111
SQL> insert into MY_TABLE
2 select *
3 from MY_HUGE_GREAT_FAT_TABLE
4 where LOAD_DATE > sysdate - 1;

105. 112
SQL> alter system kill session '123,456' immediate

107. 114
18c

108. 115
SQL> alter system cancel sql '123,456';

110. 117
speaking of "#1 reason"

111. 118
#1 reason for upgrading to 19c
developers

112. 119
SQL> select deptno, ename
2 from emp
3 order by 1,2;
DEPTNO ENAME
---------- ----------
10 CLARK
10 KING
10 MILLER
20 ADAMS
20 FORD
20 JONES
20 SCOTT
20 SMITH
30 ALLEN
30 BLAKE
30 JAMES
30 MARTIN
30 TURNER
30 WARD

113. 120
DEPTNO MEMBERS
---------- -------------------------------------
10 CLARK,KING,MILLER
20 SMITH,JONES,SCOTT,ADAMS,FORD
30 ALLEN,WARD,MARTIN,BLAKE,TURNER,JAMES

114. 121
how we used to do it

115. SQL> select deptno , rtrim(ename,',') enames
2 from ( select deptno,ename,rn
3 from emp
4 model
5 partition by (deptno)
6 dimension by (
7 row_number() over
8 (partition by deptno order by ename) rn
9 )
10 measures (cast(ename as varchar2(40)) ename)
11 rules
12 ( ename[any]
13 order by rn desc = ename[cv()]||','||ename[cv()+1])
14 )
15 where rn = 1
16 order by deptno;
DEPTNO ENAMES
---------- ----------------------------------------
10 CLARK,KING,MILLER
20 ADAMS,FORD,JONES,SCOTT,SMITH
30 ALLEN,BLAKE,JAMES,MARTIN,TURNER,WARD

116. SQL> select deptno,
2 substr(max(sys_connect_by_path(ename, ',')), 2) members
3 from (select deptno, ename,
4 row_number ()
5 over (partition by deptno order by empno) rn
6 from emp)
7 start with rn = 1
8 connect by prior rn = rn - 1
9 and prior deptno = deptno
10 group by deptno
11 /
DEPTNO MEMBERS
---------- ---------------------------------------------------------
30 ALLEN,WARD,MARTIN,BLAKE,TURNER,JAMES
20 SMITH,JONES,SCOTT,ADAMS,FORD
10 CLARK,KING,MILLER

117. SQL> select deptno,
2 xmltransform
3 ( sys_xmlagg
4 ( sys_xmlgen(ename)
5 ),
6 xmltype
7 (
8 '<?xml version="1.0"?><xsl:stylesheet version="1.0"
9 xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
10 <xsl:template match="/">
11 <xsl:for-each select="/ROWSET/ENAME">
12 <xsl:value-of select="text()"/>,</xsl:for-each>
13 </xsl:template>
14 </xsl:stylesheet>'
15 )
16 ).getstringval() members
17 from emp
18 group by deptno;
DEPTNO MEMBERS
---------- --------------------------------------------------------
10 CLARK,MILLER,KING,
20 SMITH,FORD,ADAMS,SCOTT,JONES,
30 ALLEN,JAMES,TURNER,BLAKE,MARTIN,WARD,

118. SQL> create or replace type string_agg_type as object
2 (
3 total varchar2(4000),
4
5 static function
6 ODCIAggregateInitialize(sctx IN OUT string_agg_type )
7 return number,
8
9 member function
10 ODCIAggregateIterate(self IN OUT string_agg_type ,
11 value IN varchar2 )
12 return number,
13
14 member function
15 ODCIAggregateTerminate(self IN string_agg_type,
16 returnValue OUT varchar2,
17 flags IN number)
18 return number,
19
20 member function
21 ODCIAggregateMerge(self IN OUT string_agg_type,
22 ctx2 IN string_agg_type)
23 return number
24 );
25 /

119. 126
11g

120. 127
SQL> select deptno,
2 listagg( ename, ',')
3 within group (order by empno) members
4 from emp
5 group by deptno;
DEPTNO MEMBERS
---------- -----------------------------------------
10 CLARK,KING,MILLER
20 SMITH,JONES,SCOTT,ADAMS,FORD
30 ALLEN,WARD,MARTIN,BLAKE,TURNER,JAMES

121. 128
except

122. SQL> select deptno
2 listagg(job,',') within group ( order by job) as jobs
3 from scott.emp
4 group by deptno
5 order by 1;
DEPTNO JOBS
--------- --------------------------------------------------
10 CLERK,MANAGER,PRESIDENT
20 ANALYST,ANALYST,CLERK,CLERK,MANAGER
30 CLERK,MANAGER,SALESMAN,SALESMAN,SALESMAN,SALESMAN

123. 131
19c

124. SQL> select deptno
2 listagg(distinct job,',') within group ( order by job) as jobs
3 from scott.emp
4 group by deptno
5 order by 1;
DEPTNO JOBS
--------- --------------------------------------------------
10 CLERK,MANAGER,PRESIDENT
20 ANALYST,CLERK,MANAGER
30 CLERK,MANAGER,SALESMAN

125. 133
since we're talking SQL

127. 135
20c

128. 136
SQL macros

129. 137
encapsulation of SQL logic

130. 138
scalar and table level encapsulation

131. 139
example: scalar

132. 140
numeric TRIM
if x < lower return lower
if x > upper return upper
otherwise return x

133. SQL> create function clip
2 (lo number, x number, hi number)
3 return number is
4 begin
5 return least(greatest(x, lo), hi);
6 end;
7 /

134. SQL> create function clip
2 (lo number, x number, hi number)
3 return varchar2 SQL_MACRO(SCALAR) is
4 begin
5 return 'least(greatest(x, lo), hi)';
6 end;
7 /

135. 143
not a PL/SQL function call

136. SQL> select
2 empno,
3 sal,
4 clip(sal, 1000, 2000) clipped
5 from scott.emp;
EMPNO SAL CLIPPED
---------- ---------- ----------
7369 800 1000
7499 1600 1600
7521 1250 1250
7566 2975 2000
...
SELECT
ename,
least(greatest(sal, :lower), :upper)
FROM emp;

137. 145
cross database migration

138. SQL> create function strpos
2 (str varchar2, sub_str varchar2)
3 return varchar2 SQLMACRO(SCALAR)
4 is
5 begin
6 return 'instr(str, sub_str)';
7 end;
8 /

139. 147
example: table

140. SQL> CREATE FUNCTION budget(dept_no number)
2 RETURN varchar2 SQL_MACRO(TABLE) IS BEGIN
3 RETURN q'[
4 SELECT
5 d.deptno,
6 SUM(e.sal) budget,
7 count(e.empno) headcount,
8 count(e.mgr) mgr_headcount
9 FROM emp e, dept d
10 WHERE d.deptno = :dept_no
11 AND e.deptno = d.deptno
12 GROUP BY d.deptno]';
13 end;

141. SQL> WITH east_coast as
2 (SELECT deptno
3 FROM dept
4 WHERE loc = 'Boston'
5 )
6 SELECT *
7 FROM budget(east_coast);

142. 150
polymorphic table macro
select *
from NJ(
sales,
products,
customers);
select *
from sales
natural join products
natural join customers

143. 151
cool but scary :-)

145. 153
back to #1 reason for upgrading to 19c
DBAs

146. 154
back to bad SQL

147. 155
maybe cancelling the SQL won't help

148. BAD
SQL

149. 157
bad SQL just keeps coming back...

150. 158
19c

151. 160
quarantine of bad SQL
elapsed time
resource consumption

152. 161
error on subsequent execution

153. 162
manually

154. SQL> set feedback on sql_id
SQL> select count(*) from scott.emp, scott.emp, scott.emp,
2 ( select 1 from dual connect by level <= 100000 );
COUNT(*)
----------
274400000
1 row selected.
SQL_ID: dcrqdagwxagth

155. SQL> declare
2 q varchar2(30);
3 begin
4 q := dbms_sqlq.create_quarantine_by_sql_id(
5 sql_id => 'dcrqdagwxagth');
6 end;
7 /
PL/SQL procedure successfully completed.
SQL> select count(*) from scott.emp, scott.emp, scott.emp,
2 ( select 1 from dual connect by level <= 100000 );
*
ERROR at line 1:
ORA-56955: quarantined plan used

156. 165
automatic via resource manager

157. ....
21
22 dbms_resource_manager.create_plan_directive(
23 PLAN=> 'EXEC_TIME_LIMIT',
24 GROUP_OR_SUBPLAN=>'CG_EXEC_TIME_LIMIT_CANCEL',
25 COMMENT=>'Kill statement after exceeding total time',
36 SWITCH_GROUP=>'CANCEL_SQL',
37 SWITCH_TIME=>10,
38 SWITCH_ESTIMATE=>false,
39 SWITCH_FOR_CALL=> TRUE
40 );
....
46 end;
47 /
PL/SQL procedure successfully completed.

158. SQL> select count(*) from emp, emp, emp,
2 ( select 1 from dual connect by level <= 50000 );
COUNT(*)
----------
27440000
Elapsed: 00:00:04.11
SQL> select count(*) from emp, emp, emp,
2 ( select 1 from dual connect by level <= 1000000 );
ERROR at line 1:
ORA-00040: active time limit exceeded - call aborted
Elapsed: 00:00:12.00

159. SQL> select count(*) from scott.emp, scott.emp, scott.emp,
2 ( select 1 from dual connect by level <= 100000 );
*
ERROR at line 1:
ORA-56955: quarantined plan used

160. SQL> desc V$SQL
Name Null? Type
---------------------- -------- ----------------------------
SQL_TEXT VARCHAR2(1000)
SQL_FULLTEXT CLOB
...
...
SQL_QUARANTINE VARCHAR2(128)
AVOIDED_EXECUTIONS NUMBER

161. 172
future

162. 173
automated diagnosis/repair

164. 175
"remember" multitenant ?

165. cool

167. cloninghotcloninghot

168. SQL> CREATE PLUGGABLE DATABASE prod_copy FROM prod
2 FILE_NAME_CONVERT=('/u01/oradata/cdb/prod',
3 '/u01/oradata/cdb/prod_copy');
Pluggable database created.
SQL> ALTER PLUGGABLE DATABASE prod_copy OPEN;

169. 186
refresh

170. SQL> conn / as sysdba
Connected.
SQL> alter pluggable database pdb_ro refresh
Table created.

171. Server1
CDB1
CDB2
Server2
create pluggable database Grey
from Grey@CDB2_Link
refresh mode auto every 2 minutes;
create pluggable database Red
from Red@CDB1_Link
refresh mode auto every 2 minutes;

172. 194
so ........ much ......... goodness

173. 195
no-one
uses
it

175. 197
IMPORTANT

176. 198
multi-tenant

177. 199
20c onwards ... non-cdb desupported

178. 200
20c onwards ... only multitenant

179. 201

180. 202
19c onwards ... 3 pluggable databases
WITH NO MULTITENANT LICENSE

181. 203
do it now !
not at upgrade

183. 205
back to our slow running SQL

184. cool

185. 207
maybe the SQL is fine...

186. 208
SQL> insert into MY_TABLE
2 select *
3 from MY_HUGE_GREAT_FAT_TABLE
4 where LOAD_DATE > sysdate - 1/24;

187. 209
SQL> insert into MY_TABLE
2 select *
3 from MY_HUGE_GREAT_FAT_TABLE
4 where LOAD_DATE > sysdate - 1/24;
need an index?

188. 210
what are REALLY do ...

190. 212
SQL> create index LET_ME_GET_BACK_TO_SLEEP
2 on MY_PROBLEM_TABLE (
3 SOME_COLUMNS );

192. 214
what are MEANT to do ...

193. 215
1) extract candidate SQL statements
2) consider candidate indexes per SQL
3) consolidate overlaps
4) create invisible/unusable
5) check "virtual" explain plan

194. 216
6) create true index (as invisible)
7) test execute each SQL for benefit
8) decide on index benefit for each SQL
9) SPM to avoid regressions
10) make new indexes visible

195. 217
every
15
minutes

197. 219
19c automatic indexes

198. 220
follows the best practice

199. 225
very cool ...

200. 226
... much more to be done
FK locking
compression
coalesce
IOT
etc

202. 228
statistics

203. 229
what most of us do

204. Gather
Stale
overnight

205. 231
19c

206. Conventional
DML
Real-time
Statistics
Gathered Statistics
Lightweight
Statistics

207. 233
real time statistics
DML driven

208. 234
only "cheap" essential statistics
high/low values
row/column counts

209. 235
lightweight rapid gather
resource manager

211. THIS

212. IS

213. THE

214. BIG

215. ONE

216. 242
18c XE

217. 243
100% free

218. 244
We grant you a nonexclusive, nontransferable limited license to use the programs for:
(a) purposes of developing, prototyping and running your applications for your own internal data
processing operations;
(b) you may also distribute the programs with your applications;
(c) you may use the programs to provide third party demonstrations and training; and
d) you may copy and distribute the programs to your licensees provided that each such licensee
agrees to the terms of this Agreement
https://www.oracle.com/technetwork/licenses/db18c-express-license-5137264.html

219. 245
12 GB of user data
2 GB of database RAM
2 CPU threads
3 Pluggable Databases

220. 246
"Is it feature hobbled?"

221. Oracle Multitenant
SQLJ
Online index rebuild
Online table reorg
Online table redefinition
Trial recovery
Fast start recovery
Flashback table
Flashback query
Flashback database
Advanced Queueing
Network Compression
Client side result cache
Server side result cache
Adaptive plans
In-memory column store
In-memory aggregation
Attribute Clustering
Column encryption
Tablespace encryption
Advanced Security
Database Vault
Label Security
AD users
Privilege Analysis
Real Application Security
Data Redaction
Virtual Private Database
Spatial
Graph
Partitioning
Advanced Analytics
Advanced Compression
Advanced Index Compression
Transportable Tablespace
Query Rewrite

222. 248
EE plus most extra cost options

224. 250
free multitenant + free XE

225. 251

226. 252
I lied .....

227. THIS

228. IS

229. THE

231. ONE

232. oracle.com/gbtour
New Free Tier
Always Free
Oracle Cloud Infrastructure
Services you can use for unlimited time
30-Day Free Trial
Free credits you can use for more services
+

233. Autonomous
Database
2 x Databases
20GB Storage Each
Load
Balancing
10 Mbps
Bandwidth
Shape
Storage
2 x 50GB Block
10GB Object
10GB Archive
Compute
2 x VM
1GB Memory
Each

234. FREE FOREVER

235. https://dgielis.blogspot.com/2019/09/best-and-cheapest-oracle-apex-hosting.html

236. 262
wrap up

237. 263
18c, 19c, 20c, ......

238. 264
satisfying both customer types

239. 265
lots not covered today

240. 266
you can check it out all for free

241. 267
Thanks for coming !
youtube bit.ly/youtube-connor
blog connor-mcdonald.com
twitter @connor_mc_d