added about date

Author: AnuragAnalog

README.md

@@ -351,4 +351,14 @@ select rand();
 #### Typecast to Int
 ```sql
 select cast(23.01245 as signed);
+```
+
+#### Extract Month
+```sql
+select month("1998-12-30");
+```
+
+#### Extract Year
+```sql
+select year("1998-12-30");
 ```