SHOW INDEXES [FROM|IN]

SHOW INDEXES [FROM|IN] 语句用于列出指定表上的索引。SHOW INDEX [FROM | IN] 和 SHOW KEYS [FROM | IN] 是该语句的别名。包含该语句提供了 MySQL 兼容性。

语法图

ShowIndexStmt

SHOW INDEXES - 图1

ShowLikeOrWhere

SHOW INDEXES - 图2

  1. ShowIndexStmt ::=
  2.     "SHOW" ( "INDEX" | "INDEXES" | "KEYS" ) ("FROM" | "IN" ) TableName (("FROM" | "IN") SchemaName )? ShowLikeOrWhere?
  4. ShowLikeOrWhere ::=
  5.     "LIKE" SimpleExpr
  6. |   "WHERE" Expression

示例

  1. CREATE TABLE t1 (id int not null primary key AUTO_INCREMENT, col1 INT, INDEX(col1));
  1. Query OK, 0 rows affected (0.12 sec)
  1. SHOW INDEXES FROM t1;
  1. +-------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+---------+------------+
  2. | Table | Non_unique | Key_name | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment | Index_comment | Visible | Expression |
  3. +-------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+---------+------------+
  4. | t1    |          0 | PRIMARY  |            1 | id          | A         |           0 |     NULL | NULL   |      | BTREE      |         |               | YES     | NULL       |
  5. | t1    |          1 | col1     |            1 | col1        | A         |           0 |     NULL | NULL   | YES  | BTREE      |         |               | YES     | NULL       |
  6. +-------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+---------+------------+
  7. 2 rows in set (0.00 sec)
  1. SHOW INDEX FROM t1;
  1. +-------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+---------+------------+
  2. | Table | Non_unique | Key_name | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment | Index_comment | Visible | Expression |
  3. +-------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+---------+------------+
  4. | t1    |          0 | PRIMARY  |            1 | id          | A         |           0 |     NULL | NULL   |      | BTREE      |         |               | YES     | NULL       |
  5. | t1    |          1 | col1     |            1 | col1        | A         |           0 |     NULL | NULL   | YES  | BTREE      |         |               | YES     | NULL       |
  6. +-------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+---------+------------+
  7. 2 rows in set (0.00 sec)
  1. SHOW KEYS FROM t1;
  1. +-------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+---------+------------+
  2. | Table | Non_unique | Key_name | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment | Index_comment | Visible | Expression |
  3. +-------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+---------+------------+
  4. | t1    |          0 | PRIMARY  |            1 | id          | A         |           0 |     NULL | NULL   |      | BTREE      |         |               | YES     | NULL       |
  5. | t1    |          1 | col1     |            1 | col1        | A         |           0 |     NULL | NULL   | YES  | BTREE      |         |               | YES     | NULL       |
  6. +-------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+---------+------------+
  7. 2 rows in set (0.00 sec)

注意为了兼容 MySQL，TiDB 在语法上支持 HASH、BTREE 和 RTREE 等索引类型，但会忽略它们。

MySQL 兼容性

SHOW INDEXES [FROM|IN] 语句与 MySQL 完全兼容。如发现任何兼容性差异，请尝试 TiDB 支持资源。

另请参阅