CODEWITHSUNDEEP
mysqlcachingselectsorting
pedmillon
pedmillon

Reputation: 143

MySQL SELECT on sorted data

I have a table, where one column is sorted. Does MySQL somehow check if it's sorted or not? If I make such a query SELECT from tab WHERE col1>890 AND col1<74893798 where the col1 is sorted, is it the same as e.g. SELECT from tab WHERE id>16 AND id<798176 I was unable to test this properly because of lack of admin rights to flush the query cache. To make it clear, the col1 is sorted, because it was inserted there from another table which had been sorted by the column.

Upvotes: 0

Views: 48

Answers (2)

Robert Columbia
Robert Columbia

Reputation: 6418

MySQL does not sort results by default (What drive the natural result order for an unordered MySQL request). Generally, Relational DataBase Management Systems (RDBMS) do not guarantee any specific row order unless you specify an order with an ORDER BY clause.

The advantage of this is that the database may internally sort data in whatever format it deems to be most optimal.

Upvotes: 1

charmeleon
charmeleon

Reputation: 2755

No, it is not sorted by the column you use on your where clause. The id records look sorted because that's probably your primary key and already dictates the position of the data in your table. You need to add ORDER BY column if you want your data sorted

Upvotes: 1

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