Re^2: fetchall_arrayref hangs with placeholders query with no results

Maybe having no table confuses the system?

It should not. Executing a table-less query like

SELECT 42 AS result
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works on most SQL databases. The remaining ones, Oracle being probably the most known example, always expects a dummy table or view, but also always provides that dummy table or view specifically for this purpose. Its name is DUAL on Oracle, and you need to use

SELECT 42 AS result FROM dual
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on Oracle. Some databases also provide a table or view named DUAL just for Oracle compatibility.

See Wikipedia: DUAL table for a nice overview.

Alexander

--
Today I will gladly share my knowledge and experience, for there are no sweeter words than "I told you so". ;-)

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Re^3: fetchall_arrayref hangs with placeholders query with no results by erix (Prior) on Apr 18, 2021 at 11:18 UTC
I know. PostgreSQL, for instance, knows how to since time immemorial (and certainly all maintained versions). SQL Server too (I checked all the same on sqlfiddle). In fact, I was writing a post to Marshall containing pretty much everything that you said... Anyhow, it seems the OP has lost interest, or maybe solved his problem.	[reply]
Re^4: fetchall_arrayref hangs with placeholders query with no results by TieUpYourCamel (Scribe) on Apr 21, 2021 at 15:21 UTC
Still interested, just busy. My problem isn't solved, but I have an okay workaround for now: I'm not using placeholders in any of my queries. The other things that cause the hang (specifying a TDS level and a query that produces no results) aren't really an option to not do. Connecting with no TDS level doesn't work on my production machine.	[reply]