FORCE INDEX IGNORE INDEX
MySQL :: MySQL 8.0 Reference Manual :: 8.9.4 Index Hints https://dev.mysql.com/doc/refman/8.0/en/index-hints.html
MySQL :: MySQL 8.0 Reference Manual :: 8.9.3 Optimizer Hints https://dev.mysql.com/doc/refman/8.0/en/optimizer-hints.html#optimizer-hints-index-level
Mysql中的force index和ignore index - 博客园 https://www.cnblogs.com/sdadx/p/8391985.html
明明表中有这个索引，但mysql的force index 无效？_force index 不生效 CSDN博客 https://blog.csdn.net/LJFPHP/article/details/99989001
sql优化器
CREATE TABLE `t0` (
`id` INT(11) NOT NULL AUTO_INCREMENT,
`v` INT(11) NULL DEFAULT NULL,
`uid` INT(11) NULL DEFAULT NULL,
PRIMARY KEY (`id`) USING BTREE,
INDEX `idx_v` (`v`) USING BTREE,
INDEX `idx_uid` (`uid`) USING BTREE
)
COLLATE='utf8_unicode_ci'
ENGINE=InnoDB
;
EXPLAIN SELECT * FROM t0 WHERE v>1 AND uid=123;
EXPLAIN SELECT * FROM t0 FORCE INDEX (idx_v) WHERE v>1 AND uid=123;
