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Tip of the Day
Language: VB4,VB5,VB6
Expertise: beginner
Apr 29, 2000



Building the Right Environment to Support AI, Machine Learning and Deep Learning

Avoid error 1540 in Join queries

When you plan your queries, you should avoid the use of wildcard keyword * - which means "retrieve any field" - mainly because it may decrease performances, since the engine allocates space for the entire row; use explicit field declaration instead, such as:
SELECT field1, field2 FROM table1
Moreover, consider the row length limit when you handle ordered queries; an apparently painless query like this:
SELECT * FROM table1 INNER JOIN table2 ON table1.id = table2.id ORDER BY table2.field1
may return error 1540, if the result row length is more than 8096 bytes.
Francesco Martire
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