use Perl

• DISTINCT or ORDER BY ? (Score:1)

  by n1vux (1492)

  A wise man said any SQL query without an ORDER BY clause is a stealth bug waiting to emerge when the implicit order dependency explodes into view.

  In the customer-visit itinerary, ORDER BY may actually be a better solution than DISTINCT -- the repetition value in the BAG will be needed to help plan how long to lay over in each city, as it measures how many visits are required there. GROUP BY (City) COUNT(Customer) might be better, and would get you the equivalent of DISTINCT.

  --
  Bill
  # I had a sig when sigs were cool
  use Sig;
  • Re:DISTINCT or ORDER BY ? (Score:2)

    by autarch (914) on 2006.01.17 11:50 (#45711) Homepage Journal

    If you need to know counts that's what "GROUP BY" is for, so we can do:

    SELECT city, COUNT(customer_id) as customer_count
      FROM Customer
    GROUP BY city
    ORDER BY city

    This will have no dupes and gives you the same numerical information as a dupe-containing result, but in a nice sane way, with no need to count dupes programatically in the program that executes that query.
    

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