diff --git a/core/project_hierarchy_api.php b/core/project_hierarchy_api.php
index 96b2c1962f..79dfd89e19 100644
--- a/core/project_hierarchy_api.php
+++ b/core/project_hierarchy_api.php
@@ -172,7 +172,7 @@ function project_hierarchy_cache( $p_show_disabled = false ) {
 				  WHERE $t_enabled_clause
 				  ORDER BY p.name";
 
-	$t_result = db_query_bound( $t_query, ( $p_show_disabled ? null : array( true ) ) );
+	$t_result = db_query_bound( $t_query, ( $p_show_disabled ? array() : array( true ) ) );
 
 	$g_cache_project_hierarchy = array();
 	$g_cache_project_inheritance = array();
diff --git a/core/summary_api.php b/core/summary_api.php
index fc1aa132fc..26d21af898 100644
--- a/core/summary_api.php
+++ b/core/summary_api.php
@@ -569,7 +569,7 @@ function summary_print_by_reporter() {
 				WHERE $t_specific_where
 				GROUP BY reporter_id
 				ORDER BY num DESC";
-	$t_result = db_query_bound( $t_query, null, $t_reporter_summary_limit );
+	$t_result = db_query_bound( $t_query, array(), $t_reporter_summary_limit );
 
 	$t_reporters = array();
 	while( $t_row = db_fetch_array( $t_result ) ) {
diff --git a/core/user_api.php b/core/user_api.php
index ea90d10382..34fcf416c9 100644
--- a/core/user_api.php
+++ b/core/user_api.php
@@ -1074,7 +1074,7 @@ function user_get_accessible_subprojects( $p_user_id, $p_project_id, $p_show_dis
 					  WHERE $t_enabled_clause
 					  	 ph.parent_id IS NOT NULL
 					  ORDER BY p.name";
-		$t_result = db_query_bound( $t_query, ( $p_show_disabled ? null : array( true ) ) );
+		$t_result = db_query_bound( $t_query, ( $p_show_disabled ? array() : array( true ) ) );
 	} else {
 		$t_query = "SELECT DISTINCT p.id, p.name, ph.parent_id
 					  FROM $t_project_table p
diff --git a/manage_user_page.php b/manage_user_page.php
index 3ac101e9a2..33b729b443 100644
--- a/manage_user_page.php
+++ b/manage_user_page.php
@@ -179,7 +179,7 @@
 echo '</ul>';
 echo '</div>';
 
-$t_where_params = null;
+$t_where_params = array();
 if( $f_filter === 'ALL' ) {
 	$t_where = '(1 = 1)';
 } else if( $f_filter === 'UNUSED' ) {