Add SQL query examples

Author: mikeym88

README.md

@@ -81,9 +81,10 @@ Here is an Entity Relationship Diagram (ERD) of the database structure.
 
 ![Entity Relationship Diagram (ERD) of the database structure](images/patents_view_table.png)
 
-## Selecting Patents
+## Using SQL to Select Patents
 
-Use the following to select patents between two dates:
+The `sql` folder has some SQL scripts that might come in handy. 
+As an example, here is SQL query that selects patents between two dates:
 
 ```
 SELECT

sql/select_cited_patent_numbers_not_populated.sql

@@ -0,0 +1,9 @@
+/*
+ * Use this script to find which cited patents need to be added to the Patents table.
+ */
+SELECT
+    cited_patent_number
+FROM
+    cited_patents
+WHERE
+    cited_patent_number NOT IN (SELECT DISTINCT patent_number FROM patents);

sql/select_patents_between_two_dates.sql

@@ -0,0 +1,27 @@
+/*
+ * Use this SQL query to select patents between two dates.
+ * Uncomment the lines to retrieve the company ID and the alternate name ID.
+ */
+SELECT
+    p.patent_number as "Patent Number",
+    p.patent_title as "Patent Title",
+    -- p.company_id as "Company ID",
+    c.name as "Company Name",
+    -- p.company_alternate_name_id as "Alternate Name ID",
+    an.name as "Company Name Listed on Patent",
+    p.year,
+    p.grant_date as "Grant Date",
+    p.uspc_class as "USPC Classes"
+FROM 
+    patents as p
+JOIN 
+    companies as c
+ON
+    p.company_id = c.id
+LEFT JOIN 
+    alternate_company_names as an
+ON
+    p.company_alternate_name_id = an.id
+WHERE
+    p.grant_date > DATE("2006-01-03") AND
+    p.grant_date < DATE("2010-06-13");