SQL
`IN`
The `IN` operator checks containment of the left expression inside the set of expressions on the right hand side (RHS). The `IN` operator returns true if the expression is present in the RHS, false if the expression is not in the RHS and the RHS has no `NULL` values, or `NULL` if the expression is not in the RHS and the RHS has `NULL` values.  
```sql
SELECT 'Math' IN ('CS', 'Math');
```  
```text
true
```  
```sql
SELECT 'English' IN ('CS', 'Math');
```  
```text
false
```  
```sql
SELECT 'Math' IN ('CS', 'Math', NULL);
```  
```text
true
```  
```sql
SELECT 'English' IN ('CS', 'Math', NULL);
```  
```text
NULL
```