MySQL的几种索引模式
看一下官网的索引语法
ALTER [ONLINE|OFFLINE] [IGNORE] TABLE tbl_name [alter_specification [, alter_specification] ...] [partition_options] alter_specification: table_options | ADD [COLUMN] col_name column_definition [FIRST | AFTER col_name ] | ADD [COLUMN] (col_name column_definition,...) | ADD {INDEX|KEY} [index_name] [index_type] (index_col_name,...) [index_option] ... | ADD [CONSTRAINT [symbol]] PRIMARY KEY [index_type] (index_col_name,...) [index_option] ... | ADD [CONSTRAINT [symbol]] UNIQUE [INDEX|KEY] [index_name] [index_type] (index_col_name,...) [index_option] ... | ADD FULLTEXT [INDEX|KEY] [index_name] (index_col_name,...) [index_option] ... | ADD SPATIAL [INDEX|KEY] [index_name] (index_col_name,...) [index_option] ... | ADD [CONSTRAINT [symbol]] FOREIGN KEY [index_name] (index_col_name,...) reference_definition | ALGORITHM [=] {DEFAULT|INPLACE|COPY} | ALTER [COLUMN] col_name {SET DEFAULT literal | DROP DEFAULT} | CHANGE [COLUMN] old_col_name new_col_name column_definition [FIRST|AFTER col_name] | LOCK [=] {DEFAULT|NONE|SHARED|EXCLUSIVE} | MODIFY [COLUMN] col_name column_definition [FIRST | AFTER col_name] | DROP [COLUMN] col_name | DROP PRIMARY KEY | DROP {INDEX|KEY} index_name | DROP FOREIGN KEY fk_symbol | DISABLE KEYS | ENABLE KEYS | RENAME [TO|AS] new_tbl_name | ORDER BY col_name [, col_name] ... | CONVERT TO CHARACTER SET charset_name [COLLATE collation_name] | [DEFAULT] CHARACTER SET [=] charset_name [COLLATE [=] collation_name] | DISCARD TABLESPACE | IMPORT TABLESPACE | FORCE | ADD PARTITION (partition_definition) | DROP PARTITION partition_names | TRUNCATE PARTITION {partition_names | ALL} | COALESCE PARTITION number | REORGANIZE PARTITION partition_names INTO (partition_definitions) | EXCHANGE PARTITION partition_name WITH TABLE tbl_name | ANALYZE PARTITION {partition_names | ALL} | CHECK PARTITION {partition_names | ALL} | OPTIMIZE PARTITION {partition_names | ALL} | REBUILD PARTITION {partition_names | ALL} | REPAIR PARTITION {partition_names | ALL} | REMOVE PARTITIONING index_col_name: col_name [(length)] [ASC | DESC] index_type: USING {BTREE | HASH} index_option: KEY_BLOCK_SIZE [=] value | index_type | WITH PARSER parser_name | COMMENT 'string' table_options: table_option [[,] table_option] ... (see CREATE TABLE options) partition_options: (see CREATE TABLE options)
MySQL的索引种类有
1.主键索引PRIMARY KEY
2.普通索引INDEX KEY
3.唯一索引UNIQUE KEY
4.全文检索FULLTEXT KEY