Divide count of Table 1 by count of Table 2 on the same time interval

Question

I have two tables with ID and time stamp. Table 1 has two columns: Cust_id and cust_created. Table 2 has two columns: Cust_id and post_date. I'd like to create a chart in Tableau that displays the Number of Records in Table 1 divided by Number of Records in Table 2, by week. 

Answer 1

Use a custom SQL to create a new data source

SELECT created_table.created_date,
   created_table.created_count,
   posted_table.posted_count
FROM (SELECT TRUNC (cust_created) AS created_date, COUNT (*) AS created_count
      FROM Table1) created_table
   LEFT JOIN
   (SELECT TRUNC (post_date) AS posted_date, COUNT (*) AS posted_count
      FROM Table2) posted_table
       ON created_table.created_date = posted_table.posted_date