islam updated aggregate functions #[6,8]

Author: Islam-Imad

Basic Aggregate Functions/06 -Monthly Transactions I/README.md

@@ -31,9 +31,14 @@ Return the result table in any order.
 </details>
 <details>
       <summary>Hint#5</summary>
+       <p>
+            The <code>DATE_FORMAT(date , format)</code> function formats a date as specified.
+        </p>
+</details>
+<details>
+      <summary>Hint#6</summary>
         <p>Use <code>GROUP BY</code> clause to group a set of rows into a set of summary rows</p>
 </details>
-
 </details>
 
 <details>
@@ -64,7 +69,7 @@ Return the result table in any order.
 
 
 ```sql
-    SELECT 
+SELECT 
     DATE_FORMAT(trans_date, '%Y-%m') AS month, 
     country, 
     COUNT(state) AS trans_count, 
@@ -75,9 +80,9 @@ Return the result table in any order.
     SUM(
         CASE WHEN state = 'approved' THEN amount ELSE 0 END
     ) AS approved_total_amount 
-    FROM 
+FROM 
     Transactions 
-    GROUP BY 
+GROUP BY 
     month, 
     country
 

Basic Aggregate Functions/08 -Game Play Analysis IV/README.md

@@ -17,7 +17,7 @@
 <details>
       <summary>Hint#2</summary>
       <p>
-        Try use <code>WITH</code> clause. It will help you to define a temporary data set. It will make your life easier.
+        Try using <code>WITH</code> clause. It will help you to define a temporary data set. It will make your life easier.
       </p>
 </details>
 <details>
@@ -29,7 +29,7 @@
 <details>
       <summary>Hint#4</summary>
       <p>
-        Try use <code>window function</code>.
+        Try using <code>window function</code>.
       </p>
 </details>
 
@@ -67,7 +67,7 @@ Then when we find a player logged in the next day of this day we should put this
   <li>  
   We will filter this table according to our condition <code>(event_date and first_login are consecutive days)</code>.
   <br>
-  We can use  <code>DATE_SUB()</code> function to subtract a given duration from <code>event_date</code> As follows<br> <code>DATE_SUB(event_date, INTERVAL 1 DAY) = first_login</code> 
+  We can use  <code>DATE_SUB()</code> function to subtract a given interval (e.g, a year , a month , ...) from <code>event_date</code> As follows<br> <code>DATE_SUB(event_date, INTERVAL 1 DAY) = first_login</code> 
   </li>
   <li>
   Finally, divide the player that satisfies the condition by the total number of player that we can calculate as a <code>subquery</code> then round the result using <code>ROUND()</code>function to round the result.