Miscellany

mysql> show index from hp1d\G
*************************** 1. row ***************************
       Table: hp1d
  Non_unique: 0
    Key_name: PRIMARY
Seq_in_index: 1
 Column_name: sym
   Collation: A
 Cardinality: NULL
    Sub_part: NULL
      Packed: NULL
        Null:
  Index_type: BTREE
     Comment:
*************************** 2. row ***************************
       Table: hp1d
  Non_unique: 0
    Key_name: PRIMARY
Seq_in_index: 2
 Column_name: pdatetime
   Collation: A
 Cardinality: 15378685
    Sub_part: NULL
      Packed: NULL
        Null:
  Index_type: BTREE
     Comment:
*************************** 3. row ***************************
       Table: hp1d
  Non_unique: 1
    Key_name: hp1d_sym_date_idx
Seq_in_index: 1
 Column_name: pdatetime
   Collation: A
 Cardinality: 11200
    Sub_part: NULL
      Packed: NULL
        Null:
  Index_type: BTREE
     Comment:
*************************** 4. row ***************************
       Table: hp1d
  Non_unique: 1
    Key_name: hp1d_sym_date_idx
Seq_in_index: 2
 Column_name: sym
   Collation: A
 Cardinality: 15378685
    Sub_part: NULL
      Packed: NULL
        Null:
  Index_type: BTREE
     Comment:
4 rows in set (0.00 sec)