Avoid error 1540 in Join queries

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 = ORDER BY table2.field1

may return error 1540, if the result row length is more than 8096 bytes.


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