> If you wanted to delete one row with values 347 200, then which row would it > be?
It *doesn't matter*! The rows are the same, so pick a row, ANY row! > Without the primary key, you're asking MySQL to guess, and it wont. Yes it will, if you use LIMIT (see my previous two mails). Otherwise, it'll happily delete all the rows that meet the criteria, whether they're duplicates or not. > >"duplicate rows are and always were a mistake in SQL", C.J.Date The guy has obviously never read William Kent's "Data and Reality". It's a book I'd still recommend to anyone working with data and particularly databases, even though it was written 35 years ago! <RANT> Why *must* every record be uniquely identifiable? Explain why... don't just throw random snippets of relational database theory at me! If I ask you to model the contents of your pockets on a database, are you going to attach some artificial key to each individual penny? Why? They each buy the same number of penny chews (showing my age!), and if you take 3 pennies away, you've still got 3 pennies less than you had before, no matter how carefully you select those 3 pennies! </RANT> <HINT> A tuple is, by definition, unique. If I have 8 rows on my database representing 8 real-world penny objects and I can delete 3 of them... are the remaining 5 rows tuples? How closely does the database model reality in this case? </HINT> Kind regards Caveat ------------------------------------------------------------------------------ October Webinars: Code for Performance Free Intel webinars can help you accelerate application performance. Explore tips for MPI, OpenMP, advanced profiling, and more. Get the most from the latest Intel processors and coprocessors. See abstracts and register > http://pubads.g.doubleclick.net/gampad/clk?id=60134791&iu=/4140/ostg.clktrk _______________________________________________ Gambas-user mailing list Gambas-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/gambas-user
