full table scan in mysql
Question
select *from REPT_AIR_PRY_HY1 RAP where (RAP.DATE_OF_ISSUE) BETWEEN "2017-10-01" AND DATE_ADD("2017-10-31", INTERVAL 1 DAY)
the explain plan of this query gives me 337243 but data s between these dates is only 55209 and there is even index is created on column DATE_OF_ISSUE . So, why it is scanning the whole table? thanks in advance
1 answers
solution1
0 2018-03-03 01:55:50
Some possibilities:
- The optimizer thinks (correctly or incorrectly) that a non-trivial percentage of the table would be needed. How many rows in the table?
- You are using MyISAM; switch to InnoDB.
- For some reason, the 'statistics' are stale. Do
ANALYZE TABLE.
To discuss further, please provide SHOW CREATE TABLE .
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