If the entry and exit timestamps are in different rows, then you simply need to do a self-join to get both. Something like: 
select time_diff(t1.timestamp, t2.timestamp)
  from the_table t1, the_table t2
 where t1.customer_id = t2.customer_id
   and ... other conditions ....

[download]
Note that I'm not sure if MySQL supports this form of joins, or if you need to use ANSI joins.

Michael

In reply to Re: MySql Timestamps by mpeppler
in thread MySql Timestamps by Agyeya

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