On 04/25/2017 08:09 PM, Serge Rielau wrote:


On Tue, Apr 25, 2017 at 9:45 AM, Konstantin Knizhnik 
<k.knizh...@postgrespro.ru> wrote:

    On 25.04.2017 19:12, Serge Rielau wrote:


            On Apr 25, 2017, at 8:11 AM, Konstantin Knizhnik <k.knizh...@postgrespro.ru 
<mailto:k.knizh...@postgrespro.ru>> wrote:
            Another problem is caused by using integer literals in context where 
parameters can not be used, for example "order by 1”.

        You will also need to deal with modifiers in types such as VARCHAR(10). 
Not sure if there are specific functions which can only deal with literals (?) 
as well.

    Sorry, I do not completely understand how presence of type modifiers can 
affect string literals used in query.
    Can you provide me some example?

SELECT ‘hello’::CHAR(10) || ‘World’, 5 + 6;

You can substitute ‘hello’, ‘World’, 5, and 6. But not 10.

I am substituting only string literals. So the query above will be transformed 
to

SELECT $1::CHAR(10) || $2, 5 + 6;

What's wrong with it?


Also some OLAP syntax like “rows preceding”

It pretty much boils down to whether you can do some shallow parsing rather 
than expending the effort to build the parse tree.

Cheers
Serge


--
Konstantin Knizhnik
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company

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