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Db2
Firebird
MariaDB
MySQL
Node.js
Oracle
Postgres
SQLite
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TimescaleDB
YugabyteDB
Developer-C 11.1
3.0
4.0
10.2
10.3
10.4
10.5
10.6
10.7
10.8
10.9
5.5
5.6
5.7
8.0
18
11g Release 2
18c
21c
23c
8.4
9.3
9.4
9.5
9.6
10
11
12
13
14
15
16
3.8
3.16
3.27
3.39
2012
2014
2016
2017
2017 (Linux)
2019
2019 (Linux)
2022
2.11
2.14
2.6
2.8
2.18
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Sakila
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AdventureWorks
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AdventureWorks
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WITH yourTable AS ( SELECT 201 AS Child, NULL AS Parent UNION ALL SELECT 201, 991 UNION ALL SELECT 201, 1020 UNION ALL SELECT 202, NULL UNION ALL SELECT 203, NULL ) SELECT child, parent FROM yourTable t1 WHERE Parent IS NOT NULL OR (Parent IS NULL AND NOT EXISTS (SELECT 1 FROM yourTable t2 WHERE t2.Child = t1.Child AND t2.Parent IS NOT NULL));
child
parent
201
991
201
1020
202
null
203
null