Re: How to ensure column names are double quoted while using execute format when building a stored procedure?

On 12/16/21 13:11, Shaozhong SHI wrote:
> When I used SQL identifier, it stopped working.  The command line gets
> interpreted as following:
>
> insert into stats select "1" as id, 'count of nulls in
> "UNIQUE_REFERENCE_NUMBER"' as checks,
> count("""UNIQUE_REFERENCE_NUMBER""") from
> points_of_interest."pointx_v2_National_Coverage_Sep21" where
> """UNIQUE_REFERENCE_NUMBER""" is null

"""UNIQUE_REFERENCE_NUMBER""" is a tip off that your are quoting the
double quotes when passing the identifier name into the format:

select format('select * from %I', '"UNIQUE_REFERENCE_NUMBER"');
format
---------------------------------------------
select * from """UNIQUE_REFERENCE_NUMBER"""

instead of doing as shown here
(https://www.postgresql.org/docs/current/functions-string.html#FUNCTIONS-STRING-FORMAT)
which is pass in just a string with no double quotes:

select format('select * from %I', 'UNIQUE_REFERENCE_NUMBER');
format
-----------------------------------------
select * from "UNIQUE_REFERENCE_NUMBER"

This:

'count of nulls in "UNIQUE_REFERENCE_NUMBER"'

is just plain incorrect syntax.

>
> I used select count("UNIQUE_REFERENCE_NUMBER") from a_table where
> "UNIQUE_REFERENCE_NUMBER" is null in SQL.
>
> It always worked.
>
> This can not be replicated in Execute Format.
>
> Regards,
>
> David
>
> On Thu, 16 Dec 2021 at 20:24, David G. Johnston
> <david(dot)g(dot)johnston(at)gmail(dot)com <mailto:david(dot)g(dot)johnston(at)gmail(dot)com>> wrote:
>
> On Thu, Dec 16, 2021 at 1:21 PM Shaozhong SHI
> <shishaozhong(at)gmail(dot)com <mailto:shishaozhong(at)gmail(dot)com>> wrote:
>
> The following command runs but does not produce results as expected.
> Execute Format('insert into stats select %L as id, %2$L as
> checks, count(%3$s) from %4$s where %5$s is null', i, 'count of
> nulls in '||col, col, t_name, col);
>
> All columns have got capital letters in.  How to ensure that the
> columns are double-quote when they are fed in as variables.
>
>
> Quoting the relevant doc section:
>
> https://www.postgresql.org/docs/current/functions-string.html#FUNCTIONS-STRING-FORMAT
> <https://www.postgresql.org/docs/current/functions-string.html#FUNCTIONS-STRING-FORMAT>
>
> type (required)
> The type of format conversion to use to produce the format
> specifier's output. The following types are supported:
>
> s formats the argument value as a simple string. A null value is
> treated as an empty string.
>
> I treats the argument value as an SQL identifier, double-quoting it
> if necessary. It is an error for the value to be null (equivalent to
> quote_ident).
>
> L quotes the argument value as an SQL literal. A null value is
> displayed as the string NULL, without quotes (equivalent to
> quote_nullable).
>
> David J.
>

--
Adrian Klaver
adrian(dot)klaver(at)aklaver(dot)com