UPDATE: All seems to be working again. See the answer from Jake Feasel (the creator of SQL Fiddle).
To summarise info from the comments as an answer and bring up to date as of writing:
- SQLFiddle was broken for about a year but as of 2017-07-07 it is working for Oracle 11g R2.
- It also seems to be broken for MS SQL Server 2008, MS SQL Server 2014 and MySQL 5.5 but MySQL 5.6 is working.
(Please comment if any of the above changes and I'll update the answer accordingly).
SQLFiddle Alternatives
- http://rextester.com has options for MySQL, Oracle, PostgreSQL and SQL Server in the "Language" dropdown (as well as the ability to save work online in a similar way to SQLFiddle).
- http://db-fiddle.com has options for MySQL 5.5 / 5.6 / 5.7 / 8.0, PostgreSQL 9.4 / 9.5 / 9.6 / 10.0 and SQLite 3.16 / 3.17 / 3.18.
- https://dbfiddle.uk has options for MariaDB 10.2 / 10.3, MySQL 8.0, Oracle 11g Release 2, Postgres 8.4 / 9.4 / 9.5 / 9.6 / 10 / 11, SQL Server 2012 / 2014 / 2016 / 2017 / 2017 (Linux) and SQLite 3.8 / 3.16 (as well as the ability to save work online in a similar way to SQLFiddle). See further discussion here.
- Suggested alternatives for Oracle are Oracle Application Express and Oracle Live SQL.
- A MySQL alternative with more limited functionality is sqlize.com.
- A clunky MySQL alternative is sqltest.net (if you can find your way around the adverts).
- As a last resort, I've occasionally seen answers that use Stack Exchange Data Explorer to create custom queries (in SQL Server 2016) that aren't based on the built-in tables. [Disclaimer: I'm not sure it's really supposed to be used for this kind of purpose.]
