diff --git a/sql-queries-10/understanding-sql-sargability/data-type-mismatch.sql b/sql-queries-10/understanding-sql-sargability/data-type-mismatch.sql
new file mode 100644
index 00000000..af79ee8c
--- /dev/null
+++ b/sql-queries-10/understanding-sql-sargability/data-type-mismatch.sql
@@ -0,0 +1,9 @@
+-- Non-Sargable (if id is INT) 
+EXPLAIN
+SELECT * FROM customers 
+WHERE id = '1001';
+
+-- Sargable 
+EXPLAIN
+SELECT * FROM customers 
+WHERE id = 1001;
\ No newline at end of file
diff --git a/sql-queries-10/understanding-sql-sargability/function-on-a-column.sql b/sql-queries-10/understanding-sql-sargability/function-on-a-column.sql
new file mode 100644
index 00000000..d7ab5c24
--- /dev/null
+++ b/sql-queries-10/understanding-sql-sargability/function-on-a-column.sql
@@ -0,0 +1,9 @@
+-- Non-Sargable 
+EXPLAIN 
+SELECT * FROM Student
+WHERE YEAR(birth_date) = 2001;
+
+-- Sargable 
+EXPLAIN 
+SELECT * FROM Student
+WHERE birth_date >= '2001-01-01' AND birth_date < '2002-01-01';
\ No newline at end of file
diff --git a/sql-queries-10/understanding-sql-sargability/leading-wildcard-in-like.sql b/sql-queries-10/understanding-sql-sargability/leading-wildcard-in-like.sql
new file mode 100644
index 00000000..2b5adf56
--- /dev/null
+++ b/sql-queries-10/understanding-sql-sargability/leading-wildcard-in-like.sql
@@ -0,0 +1,9 @@
+-- Non-sargable
+EXPLAIN 
+SELECT * FROM Student 
+WHERE name LIKE '%Po';
+
+-- Sargable
+EXPLAIN 
+SELECT * FROM Student 
+WHERE name LIKE 'Po%';
\ No newline at end of file
diff --git a/sql-queries-10/understanding-sql-sargability/main b/sql-queries-10/understanding-sql-sargability/main
new file mode 100644
index 00000000..e69de29b
diff --git a/sql-queries-10/understanding-sql-sargability/or-conditions-across-different-columns.sql b/sql-queries-10/understanding-sql-sargability/or-conditions-across-different-columns.sql
new file mode 100644
index 00000000..512ab73a
--- /dev/null
+++ b/sql-queries-10/understanding-sql-sargability/or-conditions-across-different-columns.sql
@@ -0,0 +1,10 @@
+-- non-sargable 
+EXPLAIN 
+SELECT * FROM Student
+WHERE national_id = 123345566 OR name = 'John Liu';
+
+-- Sargable
+EXPLAIN 
+SELECT * FROM Student WHERE national_id = 123345566 
+UNION 
+SELECT * FROM Student WHERE name='John Liu';
\ No newline at end of file
diff --git a/sql-queries-10/understanding-sql-sargability/sargability-in-joins.sql b/sql-queries-10/understanding-sql-sargability/sargability-in-joins.sql
new file mode 100644
index 00000000..8f3012bd
--- /dev/null
+++ b/sql-queries-10/understanding-sql-sargability/sargability-in-joins.sql
@@ -0,0 +1,15 @@
+-- non-sargable JOINs 
+EXPLAIN 
+SELECT c.name, e.semester, e.grade
+FROM Course c
+JOIN Exam e
+        ON LOWER(c.id) = LOWER(e.course_id)
+WHERE c.credits > 4;
+
+
+-- Sargable 
+EXPLAIN 
+SELECT c.name, e.semester, e.grade 
+FROM Course c 
+JOIN Exam e 
+         ON c.id = e.course_id WHERE c.credits > 4;
\ No newline at end of file