remove additional column marks (#16319)

diff --git a/docs/tutorials/tutorial-sql-null.md b/docs/tutorials/tutorial-sql-null.md
index eeddce4..37cf23a 100644
--- a/docs/tutorials/tutorial-sql-null.md
+++ b/docs/tutorials/tutorial-sql-null.md
@@ -133,7 +133,7 @@
 Druid returns the following:
 
 |`__time`|`title`|`string_value`|`numeric_value`|
-|---|---|---|---|---|---|
+|---|---|---|---|
 |`2024-01-01T01:04:00.000Z`|`example_3`|`empty`|`null`|
 |`2024-01-01T01:05:00.000Z`|`example_4`|`null`|`null`|