Re: Passing column name to a function at runtime

What you could do instead is make a language table, so that you could do:
SELECT lanugage_name, language_id FROM language_tbl WHERE language_name=$1;

Then you could join it on your other table.

Wright, George wrote:
> I have a language table (translations) with column names which are the
> language for the items in that column:
>
>
>
> english   spanish   german     etc.
>
>
>
> I am joining that table to another table on an integer id.
>
> I am trying to write a type statement and function where the name of the
> column is passed into the function. That language name appears in the
> select portion of the query:
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> #type
>
> CREATE TYPE catCats AS (classid integer, varname text, color text, lang
> text);
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>
> #function
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> CREATE OR REPLACE FUNCTION listCategories(text) RETURNS SETOF catCats AS $$
>
>   SELECT DISTINCT(classid), varname, color, $1
>
>   FROM span_classes
>
>   LEFT JOIN translations ON translations.lid = span_classes.descript_tid
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>   GROUP BY classid, varname, color, $1
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>   ORDER BY classid ASC;
>
> $$ LANGUAGE SQL;
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> #using the function
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> select * from listCategories(english);
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> If I pass in english or “english” it says column does not exist. If I
> pass in ‘english’ I get the literal english in my result set.
>
> If I substitute the literal english (with no quotes) in place of the $1
> in the function, the query returns the english values from the
> translations table correctly.
>
> I’ve tried bytea for the datatype, as well as a table alias. I don’t
> know the language column until runtime so I can’t code it in the function.
>
>
>
>
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> What am I doing wrong?
>


--
David Gardner