SELECT a.TABLE_SCHEMA,
a.TABLE_NAME,
a.index_name,
GROUP_CONCAT(column_name ORDER BY seq_in_index) AS `Columns`
FROM information_schema.statistics a
GROUP BY a.TABLE_SCHEMA,a.TABLE_NAME,a.index_name

--查找每个列对应的索引：

select a.TABLE_SCHEMA,a.TABLE_NAME,a.column_name, a.index_name,a.seq_in_index,b.Columns from information_schema.statistics a left join
(
SELECT a.TABLE_SCHEMA,
a.TABLE_NAME,
a.index_name,
GROUP_CONCAT(column_name ORDER BY seq_in_index) AS `Columns`
FROM information_schema.statistics a
GROUP BY a.TABLE_SCHEMA,a.TABLE_NAME,a.index_name
) b on a.TABLE_SCHEMA=b.TABLE_SCHEMA and a.TABLE_NAME=b.TABLE_NAME and a.index_name=b.index_name