title: How do I filter an SQL query that joins two tables, where an item is associated with too many items it is joined to?
body: <p>There are two tables: A, with rows (row_id, column1, ...) and B, with rows (column2, ...).</p>
  
  <pre><code>Select * from A
     join B on A.column1 = B.column2
  </code></pre>
  
  <p>There can be 1 or more records in table B having column2 = A.column1. Every record in B has a matching record in A, but not every record in A has records in B.</p>
  
  <p>What is an efficient query to get the <code>row_id</code> in table A, that has more than 100 records in table B associated with it?</p>