Is there a symbol I can use to have a where clause match all columns?

Question

I'm using sql parameter's and I have a query that I'd like to use for two similar queries. The first uses two where clauses the other uses only one of the clauses is there a symbol I can use for the second query to always equal true?

For example:

SELECT path, markdown
  FROM public."Comment"
  where path = 'relative/path/' AND markdown = 'here I am';

Second example:

SELECT path, markdown
  FROM public."Comment"
  where path = '/other/relative/path/' AND markdown = ALL;

All being a stand in for some symbol in the query that would make it effectively only search based on the path (because the markdown where clause would return true on all columns).

Answer 1

I do not agree with the approach you are thinking of using, but if you are dead set on using it, then I would probably structure the query like this:

SELECT path, markdown
  FROM public."Comment"
  where path = '/other/relative/path/' AND (TRUE OR markdown = 'here I am');

Essentially adding a 3rd parameter to your query .. one use case would use the 3rd param and set the 2nd param to FALSE, while another would set the 2nd param to TRUE..

Answer 2

Use this query instead:

SELECT path, markdown
FROM   public."Comment"
WHERE  path = $1
AND    ($2 IS NULL OR markdown = $2);

To ignore the second parameter, pass NULL for it.

Recent related question with more info:

• Conditional WHERE in plpgsql function

Answer 3

What language are you calling the query from? I've used query builders to add additional criteria to a base query. In this case, the query builder would add the check on markdown only if there was a value to compare it too.

The AND markdown = ALL conditional as you describe it is no different that if you had no markdown comparison in the WHERE clause.