title: SQL - Unequal left join BigQuery
body: <p>New here. I am trying to get the Daily and Weekly active users over time. they have 30 days before they are considered inactive. My goal is to create graph's that can be split by user_id to show cohorts, regions, categories, etc.</p>
  
  <p>I have created a date table to get every day for the time period and I have the simplified orders table with the base info that I need to calculate this. </p>
  
  <p>I am trying to do a Left Join to get the status by date using the following SQL Query:</p>
  
  <pre><code>WITH daily_use AS (
          SELECT
            __key__.id AS user_id
            , DATE_TRUNC(date(placeOrderDate), day) AS activity_date
          FROM `analysis.Order`
          where isBuyingGroupOrder = TRUE 
            AND testOrder = FALSE
          GROUP BY 1, 2
   ),
  dates AS (
          SELECT DATE_ADD(DATE "2016-01-01", INTERVAL d.d DAY) AS date
          FROM
            (
             SELECT ROW_NUMBER() OVER(ORDER BY __key__.id) -1 AS d
             FROM `analysis.Order`
             ORDER BY __key__.id
             LIMIT 1096
            ) AS  d
          ORDER BY 1 DESC
        )
  
  SELECT
        daily_use.user_id
      , wd.date AS date
      , MIN(DATE_DIFF(wd.date, daily_use.activity_date, DAY)) AS days_since_last_action
  FROM dates AS wd
  
  LEFT JOIN daily_use
      ON wd.date &gt;= daily_use.activity_date
      AND wd.date &lt; DATE_ADD(daily_use.activity_date, INTERVAL 30 DAY)
  
  GROUP BY 1,2
  </code></pre>
  
  <p>I am getting this Error: LEFT OUTER JOIN cannot be used without a condition that is an equality of fields from both sides of the join. In BigQuery and was wondering how can I go around this. I am using Standard SQL within BigQuery.</p>
  
  <p>Thank you</p>