[Pypgsql-devel] [ pypgsql-Bugs-1672884 ] "where x in %s" failes with single-element tuple

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Bugs item #1672884, was opened at 2007-03-03 21:34
Message generated for change (Comment added) made by andrewmcnamara
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Category: None
Group: None
Status: Open
Resolution: None
Priority: 5
Private: No
Submitted By: Larry Hastings (lhastings)
Assigned to: Nobody/Anonymous (nobody)
Summary: "where x in %s" failes with single-element tuple

Initial Comment:

This:
db.execute("delete from table where index in %s", ((1, 2, 3),) )
works fine.

But this:
db.execute("delete from table where index in %s", ((1,),) )
fails with a syntax error.

It's because PyPgSQL renders the arguments into the command, so the command fed into PostgreSQL becomes
delete from table where index in (1,);
and PostgreSQL's parser doesn't like a one-element tuple like that.

I suspect the fix is: notice when rendering a one-element tuple, and somehow remove or prevent the comma.

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Comment By: Andrew McNamara (andrewmcnamara)
Date: 2007-05-01 16:04

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In PgSQL.py, the function _quote() is responsible for this. For example:

>>> from pyPgSQL import PgSQL
>>> PgSQL._quote((1,))
'(1)'


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Comment By: Larry Hastings (lhastings)
Date: 2007-05-01 15:38

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I'm using 2.5.1, and I definitely saw the problem.  Where in the code does
it handle this case?

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Comment By: Andrew McNamara (andrewmcnamara)
Date: 2007-04-30 18:04

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You might want to check that you're using an up-to-date version of pyPgSQL
- I seem to remember this being fixed in 2.4. I use IN queries extensively
in my apps, and I haven't had a complaint about this problem for some time.

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