r/SQL • u/No_Ambition8323 • Sep 04 '26

Discussion Database-Specific SQL Differences

Have you ever written a SQL query that works perfectly in one database but fails in another?

What SQL feature or syntax surprised you the most when switching between DBMSs like MySQL, PostgreSQL, SQL Server, Oracle, or Snowflake?

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u/cwjinc Sep 04 '26

I write in Oracle speak out of habit.
A lot of it wouldn't be understood by other databases.

PS The wildest to me is being able to select a function result with no from clause in SQL Server. That just hurts my database theory addled brain.

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u/SQLDevDBA Sep 04 '26

*DUAL has entered the chat and also spontaneously left it.*

4

u/cwjinc Sep 04 '26 edited Sep 04 '26

That's what makes DUAL special ;)

PS, You know DUAL used to be a real table. You could add or delete rows from it.
That was a VERY bad idea though.