In the last episode (Nov 07), Michael Fischer said:
> Given:
>
> * A table TABLE_DESC, which is rather like a system table,
> in that it contains the names and column_names of other tables.
>
> * A table MY_TABLE, which contains "ordinary" data, and has a set
> of rows in TABLE_DESC.
>
> What I wish to do is to do
>
> SELECT MY_TABLE.*
>
> but without knowing that the name of the table is "MY_TABLE" in
> advance of submitting the query to the db, but rather discovering its
> name from TABLE_DESC in the same query.
>
> Perhaps this can be done with some combination of setting variables
> within a function or procedure, and views, but I haven't been able to
> work out a way to do it yet.
>
> The minimal
>
> set @tname := (SELECT table_name FROM table_desc WHERE id = :id);
> SELECT * FROM @tname;
>
> certainly doesn't work....although @tname does contain the expected value.
>
> Playing games with subqueries has been equally unsuccessful.
You'll need to use a prepared statement to build your query:
http://dev.mysql.com/doc/refman/5.0/en/sqlps.html
Note that you can't use placeholders for the table name itself, so
you'll need to concatenate it into the query string before preparing
it.
--
Dan Nelson
dnelson@stripped
