Re: select on multiple tables

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От Rene Pijlman
Тема Re: select on multiple tables
Дата
Msg-id ovh2ot0ne3b4qenvm21psfonor798q1e2c@4ax.com
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Ответ на Re: select on multiple tables  (Ben Carterette <bcarterette@liberty.k12.mo.us>)
Список pgsql-jdbc
On Thu, 16 Aug 2001 10:02:27 -0500, you wrote:
>This won't work because I don't know in advance of the SELECT which
>tables I'm going to be selecting from.

I'm not sure if I understand this correctly. Whenever you write
the SELECT statement you have to know the names of the tables,
that's required by the syntax of select.

What you're telling us is that you don't know the column names
when you construct the statement, but you do know the column
names 5 lines down when you want to do the rs.getString()?


>On Wednesday, August 15, 2001, at 06:29  PM, Rene Pijlman wrote:
>> On Wed, 15 Aug 2001 16:43:31 -0500, Ben Carterette wrote:
>>> I have a query like "SELECT * FROM table1, table2" and I want to read
>>> values
>>> out of a ResultSet.  What if the two tables have column names in
>>> common and
>>> I can't predict the column numbers?  Is there any way to get table1.id
>>> and
>>> table2.id?  rs.getString tells me "The column name table1.id not
>>> found."
>>
>> Does this also happen when you explicitly name the columns?
>>
>>    SELECT table1.id, ..., table2.id, ...
>>    FROM table1, table2
>>
>> Or if that doesn't help, try if a column label with the AS
>> clause works:
>>
>> SELECT [ ALL | DISTINCT [ ON ( expression [, ...] ) ] ]
>>     * | expression [ AS output_name ] [, ...]
>> http://www.postgresql.org/idocs/index.php?sql-select.html
>>
>>   SELECT table.id AS id1, ..., table2.id AS id2
>>   FROM table1, table2
>>
>> And then rs.getString("id1");
>>
>> I think both solutions should work. Please let us know if they
>> don't.
>>
>> Regards,
>> René Pijlman
>>
>
>---------------------------(end of broadcast)---------------------------
>TIP 4: Don't 'kill -9' the postmaster


Regards,
René Pijlman

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