• Two tables are involved:
    • customer c: Refer to customer as c.
    • ord o: Refer to ord as o.

  • where What follows is a predicate qualifying rows.

  • c.customer_id = o.customer_id: Connects rows of customer and ord by matching customer_id. This is a join.

  • o.ord_date between 'April 1, 2012' and 'April 30, 2012': Look for dates in April 2012.