MySQL use index () optimization query

MySQL use index () optimization query

Force Index/ignore The syntax of INDEX:

SELECT * * * from TABLE [{use| ignore| Force} INDEX (key_list)] WHERE ...

Use INDEX
After the table name in your query statement, add use index to provide the index column you want MYSQ to refer to
Table, you can let MySQL no longer consider other available indexes.
Eg:select * FROM mytable use INDEX (mod_time, name) ...

IGNORE INDEX
If you simply want MySQL to ignore one or more indexes, you can use IGNORE index as the
For Hint.
Eg:select * from Mytale IGNORE INDEX (priority) ...

Force INDEX
To force MySQL to use a specific index, you can use the forces index as Hint in the query.
Eg:select * FROM MyTable Force INDEX (mod_time) ...

MySQL use index () optimization query