diff --git a/phpBB/phpbb/db/migration/data/v310/style_update_p1.php b/phpBB/phpbb/db/migration/data/v310/style_update_p1.php
index 3e28e8747d..f50ab33830 100644
--- a/phpBB/phpbb/db/migration/data/v310/style_update_p1.php
+++ b/phpBB/phpbb/db/migration/data/v310/style_update_p1.php
@@ -165,7 +165,7 @@ class style_update_p1 extends \phpbb\db\migration\migration
 
 			$this->config->set('default_style', $default_style);
 
-			$sql = 'UPDATE ' . USERS_TABLE . ' SET user_style = ' .  $default_style;
+			$sql = 'UPDATE ' . USERS_TABLE . ' SET user_style = ' .  (int) $default_style;
 			$this->sql_query($sql);
 		}
 		else
diff --git a/phpBB/phpbb/db/migration/data/v32x/fix_user_styles.php b/phpBB/phpbb/db/migration/data/v32x/fix_user_styles.php
index e0caae812a..282c6bef2f 100644
--- a/phpBB/phpbb/db/migration/data/v32x/fix_user_styles.php
+++ b/phpBB/phpbb/db/migration/data/v32x/fix_user_styles.php
@@ -43,8 +43,8 @@ class fix_user_styles extends \phpbb\db\migration\migration
 		$this->db->sql_freeresult($result);
 
 		// Set the default style to users who have an invalid style
-		$this->sql_query('UPDATE ' . USERS_TABLE . "
-			SET user_style = $default_style
-			WHERE " . $this->db->sql_in_set('user_style', $enabled_styles, true));
+		$this->sql_query('UPDATE ' . USERS_TABLE . '
+			SET user_style = ' . (int) $default_style . '
+			WHERE ' . $this->db->sql_in_set('user_style', $enabled_styles, true));
 	}
 }