Upload 181

Author: ggeerraarrdd

README.md

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 [![eevveerryyddaayy release](https://img.shields.io/badge/eevveerryyddaayy-v1.3.0-blue.svg)](https://github.com/ggeerraarrdd/eevveerryyddaayy/)
-[![Solved](https://img.shields.io/badge/solved-180-green.svg)](#index)
+[![Solved](https://img.shields.io/badge/solved-181-green.svg)](#index)
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 # SQL Everyday
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 | 178   | [Shortest Distance in a Line](https://leetcode.com/problems/shortest-distance-in-a-line/description/)                                                             | [Solution](solutions/178_shortest_distance_in_a_line.md)                                | LeetCode    | Easy         | `SELF-JOIN` vs `CROSS JOIN`                                         |
 | 179   | [Friendly Movies Streamed Last Month](https://leetcode.com/problems/friendly-movies-streamed-last-month/description/)                                             | [Solution](solutions/179_friendly_movies_streamed_last_month.md)                        | LeetCode    | Easy         |                                                                     |
 | 180   | [Books with NULL Ratings](https://leetcode.com/problems/books-with-null-ratings/description/)                                                                     | [Solution](solutions/180_books_with_null_ratings.md)                                    | LeetCode    | Easy         |                                                                     |
+| 181   | [Customer Order Frequency](https://leetcode.com/problems/customer-order-frequency/description/)                                                                   | [Solution](solutions/181_customer_order_frequency.md)                                   | LeetCode    | Easy         | `USING`, `HAVING`                                                   |
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solutions/181_customer_order_frequency.md

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+# SQL Everyday \#181
+
+## Customer Order Frequency
+
+Site: LeetCode\
+Difficulty per Site: Easy
+
+## Problem
+
+Write a solution to report the `customer_id` and `customer_name` of customers who have spent at least `$100` in each month of **June and July 2020**.
+
+Return the result table in **any order**. [[Full Description](https://leetcode.com/problems/customer-order-frequency/description/)]
+
+## Submitted Solution
+
+```sql
+-- Submitted Solution
+WITH cte1 AS (
+    SELECT
+        c.customer_id
+        ,c.name
+        ,DATE_TRUNC('month', o.order_date) AS month
+        ,SUM(o.quantity * p.price) AS total
+    FROM Orders AS o
+    JOIN Product AS p ON o.product_id = p.product_id
+    JOIN Customers AS c ON o.customer_id = c.customer_id
+    GROUP BY c.customer_id, c.name, month
+),
+cte2 AS (
+    SELECT
+        customer_id
+        ,name
+        ,SUM(CASE WHEN (month = '2020-06-01' or month = '2020-07-01') AND total >= 100 THEN 1
+            ELSE 0 END) AS validation
+    FROM cte1
+    GROUP BY customer_id, name
+)
+SELECT
+    customer_id
+    ,name
+FROM cte2
+WHERE validation = 2
+;
+```
+
+## Site Solution
+
+```sql
+-- LeetCode Solution 
+SELECT 
+  customer_id, 
+  name 
+FROM 
+  Customers 
+  JOIN Orders USING(customer_id) 
+  JOIN Product USING(product_id) 
+WHERE 
+  YEAR(order_date)= 2020 
+GROUP BY 
+  customer_id 
+HAVING 
+  SUM(
+      IF(MONTH(order_date) = 6, quantity, 0) * price
+  ) >= 100 AND 
+  SUM(
+      IF(MONTH(order_date) = 7, quantity, 0) * price
+  ) >= 100;
+```
+
+## Notes
+
+TBD
+
+## NB
+
+`USING`, `HAVING`
+
+Go to [Index](../?tab=readme-ov-file#index)\
+Go to [Overview](../?tab=readme-ov-file)