diff --git a/SQL/lessons/.sql_3.md.swp b/SQL/lessons/.sql_3.md.swp
index 8cb3a12..0ba149d 100644
Binary files a/SQL/lessons/.sql_3.md.swp and b/SQL/lessons/.sql_3.md.swp differ
diff --git a/SQL/lessons/sql_3.md b/SQL/lessons/sql_3.md
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--- a/SQL/lessons/sql_3.md
+++ b/SQL/lessons/sql_3.md
@@ -89,6 +89,11 @@ SELECT DISTINCT city FROM people;
 
 ### Unions
 
+```sql
+SELECT name FROM people UNION SELECT name FROM companies; -- show distinct values
+SELECT name FROM people UNION ALL SELECT name FROM companies; -- show duplicates
+```
+
 ### Truncate
 
 ### Triggers