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This article mainly introduces "how to solve the pit of mysql order by limit". In the daily operation, I believe that many people have doubts about how to solve the problem of the pit of mysql order by limit. The editor consulted all kinds of materials and sorted out simple and easy-to-use operation methods. I hope it will be helpful for you to answer the doubt of "how to solve the pit of mysql order by limit"! Next, please follow the editor to study!

Pit encountered in paging query:

Problem found: after sorting a single unindexed field, limit. It is found that when the sorted field has the same value and is within the range of limit, the value taken is not the value after normal sorting.

That is, when the data in row N is preferable to key1 or key2, the sort result may be key1 or key2.

Sort + limit results (sort key has no index)

Press CNT to get key _ word, respectively, for the first three results:

Original text:

If multiple rows have identical values in the ORDER BY columns, the server is free to return those rows in any order, and may do so differently depending on the overall execution plan. In other words, the sort order of those rows is nondeterministic with respect to the nonordered columns.

This means that if the columns of order by have the same values, mysql will randomly select these rows, depending on the execution plan.

Solution: the column of order by contains an index column

Add the primary key id to the sorted column here

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