Index Columns

I seem to always have to rediscover how this works, so I'm going to record it.

This is how to join sys.indexes, sys.index_columns, and sys.columns.

SELECT ...
FROM sys.indexes        AS i
JOIN sys.index_columns  AS ic
  ON   i.[object_id] = ic.[object_id]
   AND i.index_id    = ic.index_id
JOIN sys.columns        AS c
  ON   ic.[object_id] = c.[object_id]
   AND ic.column_id   = c.column_id