What does the KEY keyword mean

Question

In this MySQL table definition   CREATE TABLE groups     ug main grp id smallint NOT NULL default  0     ug uid smallint  default NULL    ug grp id smallint  default NULL    KEY  ug main grp id       What does the KEY keyword mean  It s not a primary key  it s not a foreign key  so is it just an index  If so  what is so special about this type of index created with KEY

User · Accepted Answer

Quoting from http   dev mysql com doc refman 5 1 en create-table html   INDEX KEY    So KEY is an INDEX

User · Answer

KEY is normally a synonym for INDEX  The key attribute PRIMARY KEY can also be specified as just KEY when given in a column definition  This was implemented for compatibility with other database systems    column definition        data type  NOT NULL   NULL   DEFAULT default value         AUTO INCREMENT   UNIQUE  KEY     PRIMARY  KEY              Ref  http   dev mysql com doc refman 5 1 en create-table html

[mysql] What does the KEY keyword mean?

Examples related to mysql

Examples related to indexing