Re: Find schema of a table in a query

WOW Keith. That’s the sqlite coding equivalent of scoring a hat trick in the world cup final. I’ve added an order by to get the solution

select name from pragma_database_list d
where (select name from pragma_table_xinfo where schema==d.name and arg==?1)
order by seq!=1, seq limit 1;

I’m assuming the temp db is always 1 in the seq column. Can anyone confirm that or should I change it to

order by lower(name)!=temp, seq limit 1;

Thanks. I also learned the parentheses are not required for pragma functions when there’s no params and alternate syntax when they are.


________________________________
From: sqlite-users <[email protected]> on behalf of Keith Medcalf <[email protected]>
Sent: Sunday, January 19, 2020 8:32:06 PM
To: SQLite mailing list <[email protected]>
Subject: Re: [sqlite] Find schema of a table in a query


On Sunday, 19 January, 2020 01:47, x <[email protected]> wrote:

>Suppose you’re given a query ‘SELECT 1 from tbl’ by a user and you want
>to know the name of the schema that tbl belongs to. What’s the easiest
>way to do this?

>I know sqlite will use temp.tbl if it exists else main.tbl if it exists
>else it will search for the earliest attached schema with a table called
>tbl. Finding that involves the use of PRAGMA database_list and then
>querying each of the associated sqlite_master tables in turn for the
>existence of tbl until you get a match. Is there an easier way?

How about:

select name
  from pragma_database_list as d
 where (select name
          from pragma_table_xinfo
         where schema == d.name
           and arg == 'x') is not null;

Where you set "arg == 'tablename'" which will return all the schema's in which the specified tablename exists.

--
The fact that there's a Highway to Hell but only a Stairway to Heaven says a lot about anticipated traffic volume.



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