feat: add sql solutions to lc problems: No.1068,1069,1070

Author: yanglbme

solution/1000-1099/1068.Product Sales Analysis I/README.md

@@ -79,7 +79,17 @@ Result 表：
 ### **SQL**
 
 ```sql
-
+# Write your MySQL query statement below
+SELECT
+    p.product_name AS product_name,
+    s.year AS year,
+    s.price AS price
+FROM
+    Sales s
+LEFT JOIN
+    Product p
+ON
+    s.product_id = p.product_id;
 ```
 
 <!-- tabs:end -->

solution/1000-1099/1068.Product Sales Analysis I/README_EN.md

@@ -85,7 +85,17 @@ From sale_id = 7, we can conclude that Apple was sold for 9000 in the year 2011.
 ### **SQL**
 
 ```sql
-
+# Write your MySQL query statement below
+SELECT
+    p.product_name AS product_name,
+    s.year AS year,
+    s.price AS price
+FROM
+    Sales s
+LEFT JOIN
+    Product p
+ON
+    s.product_id = p.product_id;
 ```
 
 <!-- tabs:end -->

solution/1000-1099/1068.Product Sales Analysis I/Solution.sql

@@ -0,0 +1,11 @@
+# Write your MySQL query statement below
+SELECT
+    p.product_name AS product_name,
+    s.year AS year,
+    s.price AS price
+FROM
+    Sales s
+LEFT JOIN
+    Product p
+ON
+    s.product_id = p.product_id;

solution/1000-1099/1069.Product Sales Analysis II/README.md

@@ -77,7 +77,14 @@ Result 表：
 ### **SQL**
 
 ```sql
-
+# Write your MySQL query statement below
+SELECT
+    product_id,
+    sum(quantity) AS total_quantity
+FROM
+    Sales
+GROUP BY
+    product_id;
 ```
 
 <!-- tabs:end -->

solution/1000-1099/1069.Product Sales Analysis II/README_EN.md

@@ -135,7 +135,14 @@ Result table:
 ### **SQL**
 
 ```sql
-
+# Write your MySQL query statement below
+SELECT
+    product_id,
+    sum(quantity) AS total_quantity
+FROM
+    Sales
+GROUP BY
+    product_id;
 ```
 
 <!-- tabs:end -->

solution/1000-1099/1069.Product Sales Analysis II/Solution.sql

@@ -0,0 +1,8 @@
+# Write your MySQL query statement below
+SELECT
+    product_id,
+    sum(quantity) AS total_quantity
+FROM
+    Sales
+GROUP BY
+    product_id;

solution/1000-1099/1070.Product Sales Analysis III/README.md

@@ -75,7 +75,22 @@ Result table:
 ### **SQL**
 
 ```sql
-
+# Write your MySQL query statement below
+SELECT
+    product_id,
+    year as first_year,
+    quantity,
+    price
+FROM
+    Sales
+WHERE
+    (product_id, year) IN (
+        SELECT 
+            product_id, min(year) year
+        FROM
+            Sales
+        GROUP BY product_id
+    );
 ```
 
 <!-- tabs:end -->

solution/1000-1099/1070.Product Sales Analysis III/README_EN.md

@@ -137,7 +137,22 @@ Result table:
 ### **SQL**
 
 ```sql
-
+# Write your MySQL query statement below
+SELECT
+    product_id,
+    year as first_year,
+    quantity,
+    price
+FROM
+    Sales
+WHERE
+    (product_id, year) IN (
+        SELECT 
+            product_id, min(year) year
+        FROM
+            Sales
+        GROUP BY product_id
+    );
 ```
 
 <!-- tabs:end -->

solution/1000-1099/1070.Product Sales Analysis III/Solution.sql

@@ -0,0 +1,16 @@
+# Write your MySQL query statement below
+SELECT
+    product_id,
+    year as first_year,
+    quantity,
+    price
+FROM
+    Sales
+WHERE
+    (product_id, year) IN (
+        SELECT 
+            product_id, min(year) year
+        FROM
+            Sales
+        GROUP BY product_id
+    );