Creating an array with dynamic query in PL / pgSQL

I am trying to create an array with a dynamic selection request in the plpgsql function. Sorry, I am getting a syntax error.

ERROR:  syntax error at or near "EXECUTE"
ZEILE 19:  SELECT DISTINCT INTO outputIdsToDelete ARRAY( EXECUTE findA...
                                                         ^

Can someone help me? Here is the function itself:

CREATE OR REPLACE FUNCTION deleteMAPPINGs (
   mapTable1_key text, mapping_table text, mapTable2_key text,
   table2 text, table2_key text,
   inputIdsToDelete bigint []) RETURNS bigint [] AS
$ BODY $
Decare
    outputIdsToDelete bigint [];
    findAllQuery text;
    findUnreferencedQuery text;
    BEGIN
    findAllQuery: = 'SELECT DISTINCT' || mapTable2_key ||
        'FROM' || mapping_table ||
        'WHERE' || mapTable1_key || '= ANY (inputIdsToDelete)';
    findUnreferencedQuery: = 'SELECT DISTINCT' || table2_key || --find unused
        'FROM' || table2 ||
        'WHERE' || table2_key || 'NOT IN (' ||
            'SELECT DISTINCT' || mapTable2_key || --all used
            'FROM' || mapping_table || ')';

    SELECT DISTINCT INTO outputIdsToDelete ARRAY (EXECUTE findAllQuery);

    DELETE FROM mapping_table WHERE 
        mapTable1_key = ANY (inputIdsToDelete) AND
        mapTable2_key = ANY (outputIdsToDelete);

    SELECT DISTINCT INTO outputIdsToDelete --overwrite with unused
        ARRAY (EXECUTE findUnreferencedQuery);

    RETURN outputIdsToDelete;
END
$ BODY $
LANGUAGE plpgsql VOLATILE
COST 100;