インデックスを表示[FROM|IN]

ステートメントSHOW INDEXES [FROM|IN]は、指定されたテーブルのインデックスをリストします。ステートメントSHOW INDEX [FROM|IN]はこのステートメントのエイリアスであり、MySQLとの互換性のために含まれてSHOW KEYS [FROM|IN]ます。

あらすじ

ShowIndexStmt:

ShowIndexStmt

ShowIndexKwd:

ShowIndexKwd

FromOrIn:

FromOrIn

TableName:

TableName

ShowLikeOrWhereOpt:

ShowLikeOrWhereOpt

mysql> CREATE TABLE t1 (id int not null primary key AUTO_INCREMENT, col1 INT, INDEX(col1)); Query OK, 0 rows affected (0.12 sec) mysql> SHOW INDEXES FROM t1; +-------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+---------+------------+ | Table | Non_unique | Key_name | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment | Index_comment | Visible | Expression | +-------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+---------+------------+ | t1 | 0 | PRIMARY | 1 | id | A | 0 | NULL | NULL | | BTREE | | | YES | NULL | | t1 | 1 | col1 | 1 | col1 | A | 0 | NULL | NULL | YES | BTREE | | | YES | NULL | +-------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+---------+------------+ 2 rows in set (0.00 sec) mysql> SHOW INDEX FROM t1; +-------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+---------+------------+ | Table | Non_unique | Key_name | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment | Index_comment | Visible | Expression | +-------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+---------+------------+ | t1 | 0 | PRIMARY | 1 | id | A | 0 | NULL | NULL | | BTREE | | | YES | NULL | | t1 | 1 | col1 | 1 | col1 | A | 0 | NULL | NULL | YES | BTREE | | | YES | NULL | +-------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+---------+------------+ 2 rows in set (0.00 sec) mysql> SHOW KEYS FROM t1; +-------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+---------+------------+ | Table | Non_unique | Key_name | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment | Index_comment | Visible | Expression | +-------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+---------+------------+ | t1 | 0 | PRIMARY | 1 | id | A | 0 | NULL | NULL | | BTREE | | | YES | NULL | | t1 | 1 | col1 | 1 | col1 | A | 0 | NULL | NULL | YES | BTREE | | | YES | NULL | +-------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+---------+------------+ 2 rows in set (0.00 sec)

MySQLの互換性

MySQLのCardinality列は、インデックスのさまざまな値の数を示しています。 TiDBでは、 Cardinality列には常に0が表示されます。

も参照してください

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