Re: Unpacking a Python list in a query.

"UPDATE foobartable SET name = 'FooBar' WHERE name in (%s)"

And pass your list as a parameter (it must be a tuple).

execute("UPDATE foobartable SET name = 'FooBar' WHERE name in (%s)",
(tuple(yourlist),))

That should work.

2011/6/24 Sukhbir Singh <singheinstein(at)gmail(dot)com>

> Hi,
>
> I am using the psycopg2 adapter on Python 2.6.
>
> There was a requirement to automate certain UPDATE queries, so I
> designed the program in such a way that the end of the queries are in
> a list. I will illustrate with an example.
>
> The query is:
>
> UPDATE foobartable SET name = 'FooBar' WHERE name = %s OR name = %s
>
> And say I have a list:
>
> ["Foo", "Bar"]
>
> So, I want to execute the complete query as: substituting element by
> element from the list for each %s:
>
> UPDATE foobartable SET name = 'FooBar' WHERE name = 'Foo' OR name =
> 'Bar'
>
> The question is: how do I pass this list to the query?
>
> I tried using the format method and list unpacking (*list) and it
> works. But the docs recommend otherwise: "Warning Never, never, NEVER
> use Python string concatenation (+) or string parameters interpolation
> (%) to pass variables to a SQL query string. Not even at gunpoint"
> This is what I did:
>
> curr.execute("UPDATE foobartable SET name='FooBar' WHERE
> name='{0}' or name='{1}';".format(*list))
>
> ... which I am certain is wrong.
>
> How can I get this working with something safe and the recommended way
> of doing it?
>
> --
> Sukhbir.
>
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