Low Search + Matrix field data

Question

I'm trying to create a dropdown of matrix field data using the search form. It's outputting the matrix data, but I can't seem to figure out how to remove duplicate content. Say I'm using the data "john doe" on multiple entries -- it's showing for every entry, not just once. Is there any way to fix this? Thanks in advance.

{exp:low_search:form query="{segment_3}"}   
    <label>Arranger:</label>
    <select name="search:tags:arranger">
        {exp:channel:entries channel="products" dynamic="no"}
            {tags}<option value="{arranger}">{arranger}</option>{/tags}
        {/exp:channel:entries}
    </select>
    <button type="submit">Search</button>
{/exp:low_search:form}

Answer 1

You'll need to use the Query module for this. Something like

{exp:query sql="SELECT DISTINCT col_id_X AS val FROM exp_matrix_data WHERE field_id = Y ORDER BY val"}
  <option>{val}</option>
{/exp:query}

...where you need to replace X with the correct column ID and Y with the correct field ID.

EDIT Alternatively, you can try this query:

{exp:query sql="SELECT col_id_X AS val FROM exp_matrix_data WHERE field_id = Y AND col_id_X != '' GROUP BY col_id_X ORDER BY val"}
  <option>{val}</option>
{/exp:query}