For MySQL multi table query, the data found by indexing is different from that without index

CSDN Q & A 2022-02-13 08:28:33 阅读数:249

mysql multi table query data

mysql Multi-table query , The data that is indexed and queried without index are different




Take the answer :

What is it like sql And data , Post it to see



Other answers 2:

https://bbs.csdn.net/topics/392158859, Turn out an old post , Index file corruption may cause the difference between the results with and without index

Another possibility is , Full text index word segmentation may be similar to like The results are different , I don't know what your situation is


Other answers 3:

The index has nothing to do with the queried data , But it has something to do with the time when the data is queried , So your question should have nothing to do with the index !


Other answers 4:

First, it's impossible , Indexing is just a way to improve retrieval efficiency . The result is different, just the appearance ,sql Adding an index leaves out the fields with empty index fields , No, it's all found . If help , Please accept !


Other answers 5:

Indexes are built on Columns , A data structure that sorts columns . The function is to speed up the query .
There are more data in the table , The index is used only when the data in the column is neat Small tables or fields often change, which is unnecessary .
where There are conditions <> !=
where There are conditions Aggregate functions
Fuzzy query %xxx
There are a lot of duplicate data in the column When the index is invalid ;
Neither will affect the query data Just for efficiency It should be you sql The problem has nothing to do with the index


Other answers 6:

No plan, no truth , Unless BUG 了 . this ... You first upgrade to the latest version to see .

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