diff --git a/3.sql b/3.sql
index 4dee596..462576d 100644
--- a/3.sql
+++ b/3.sql
@@ -1,2 +1,2 @@
 -- write a SQL query to find the ids of rows for which a value in the column debut is missing.
-SELECT "id" FROM "players" WHERE "debut" = "NULL";
+SELECT "id" FROM "players" WHERE "debut" IS NULL;
diff --git a/4.sql b/4.sql
index e69de29..90b1ea3 100644
--- a/4.sql
+++ b/4.sql
@@ -0,0 +1,3 @@
+-- write a SQL query to find the first and last names of players who were not born in the United States.
+-- Sort the results alphabetically by first name, then by last name.
+SELECT "first_name", "last_name" FROM "players" WHERE "birth_country" != "USA" ORDER BY "first_name" ASC, "last_name" ASC;