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SHOW INDEXES
Show the list of indexes associated with a given table.
Syntax
SHOW INDEXES
{FROM | IN} tbl_name
[{FROM | IN} db_name]
[WHERE expr]
Remarks
tbl_name- name of a table in a MemSQL database.db_name- name of a MemSQL database.expr- SQL WHERE expression.- This command must be run on the master aggregator or a child aggregator node (see Node Requirements for MemSQL Commands).
Output
| Column | Description |
|---|---|
Table |
Table name |
Non_unique |
1 if non-unique, 0 if unique |
Key_name |
Index (key) name |
Seq_in_index |
Ordinal position of key column in index |
Column_name |
Column name (keys can have one or more columns) |
Collation |
Collation of string column, if applicable |
Cardinality |
Always NULL (not applicable in MemSQL) |
Sub_part |
Always NULL (not applicable in MemSQL) |
Packed |
Always NULL (not applicable in MemSQL) |
Null |
YES if values in the key column can be NULL, else blank |
Index_type |
The type of index. If index type is BTREE, then index is a MemSQL skip list. See Index |
Comment |
Always blank (not used in MemSQL) |
Index_comment |
Always blank (not used in MemSQL) |
Example
memsql> SHOW INDEXES IN mytbl;
+-------+------------+-----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
| Table | Non_unique | Key_name | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment | Index_comment |
+-------+------------+-----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
| mytbl | 1 | seq | 1 | seq | NULL | NULL | NULL | NULL | YES | BTREE | | |
| mytbl | 1 | seq_index | 1 | seq | NULL | NULL | NULL | NULL | YES | BTREE | | |
+-------+------------+-----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
2 rows in set (0.00 sec)
