MySQL in a Nutshell, 2nd Edition

Name

SHOW INDEXES

Synopsis

SHOW {INDEX|INDEXES|KEYS} FROM table [FROM database]

This SQL statement displays information about the indexes for a given table. A table from a different database can be specified either by preceding the table name with the database name and a dot (e.g., database.table) or by adding the FROM clause. The INDEXES keyword may be replaced with INDEX or KEYS—all three are synonymous:

SHOW INDEXES FROM contacts FROM sales_dept \G

*************************** 1. row ***************************
       Table: contacts
  Non_unique: 0
    Key_name: PRIMARY
Seq_in_index: 1
 Column_name: contact_id
   Collation: A
 Cardinality: 265
    Sub_part: NULL
      Packed: NULL
        Null: 
  Index_type: BTREE
     Comment: 
*************************** 2. row ***************************
       Table: contacts
  Non_unique: 0
    Key_name: contact_name
Seq_in_index: 1
 Column_name: name_last
   Collation: A
 Cardinality: NULL
    Sub_part: 10
      Packed: NULL
        Null: YES
  Index_type: BTREE
     Comment: 
*************************** 3. row ***************************
       Table: contacts
  Non_unique: 0
    Key_name: contact_name
Seq_in_index: 2
 Column_name: name_first
   Collation: A
 Cardinality: NULL
    Sub_part: 10
      Packed: NULL
        Null: YES
  Index_type: BTREE
     Comment: 

Looking at these results, we can see that for each index the table name is given. This is followed by a field indicating whether the index is nonunique. A unique index is indicated by 0, a nonunique index by 1. The name of the index or key (i.e., PRIMARY or contact_name in the example) is shown next. For indexes ...