null
BigQuery
Db2 (LUW)
MariaDB
MySQL
Oracle DB
PostgreSQL
SQL Server
SQLite
2005
2007
2009
2011
2013
2015
2017
2019
2021
2023
✓ 3.44.0 - 3.50.0
b
✓ 3.5.7 - 3.43.0
✓ 2012 - 2022
b
✓ 2008R2
✓ 9.1 - 18
b
✓ 8.4 - 9.0
⚠ 8.3
⚠ 11gR1 - 23.26.0
a
b
✓ 5.0 - 9.5.0
✓ 5.1 - 12.0.2
✓ 9.7 - 12.1.2
✓ 2.0
Empty string
is null
.
||
treats
null
as empty string
concat()
treats
null
as empty string