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mattt
Posting Yak Master
194 Posts |
 Posted - 2001-11-14 : 09:39:07
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| Hi, Anyone fancy helping me understand why these two SQL statements, which ought to return the same data set have such a huge performance difference that the returns records in about five seconds and the second one won't return any, even after an hour? 1) SELECT DISTINCT * FROM books INNER JOIN authorsonbooks ON books.bookref = authorsonbooks.bookref INNER JOIN authors ON authorsonbooks.authorID = authors.authorID WHERE authors.authors LIKE '%adair%' OR authors.authorLName LIKE '%adair%' 2)SELECT DISTINCT * FROM books, authors, authorsonbooks WHERE books.bookref = authorsonbooks.bookref AND authorsonbooks.authorID = authors.authorID AND authors.authors LIKE '%adair%' OR authors.authorLName LIKE '%adair%' if I can get awway without using the joins, building the query (from data entered into a form) is going to be an awful lot easier. Besides, I'm not sure how I can work more than one set of unrelated tables into a join. |
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SQL joins and performance