I need a query to see if a table already has any indexes on it.
On Oracle:
Determine all indexes on table:
SELECT index_name
FROM user_indexes
WHERE table_name = :table
Determine columns indexes and columns on index:
SELECT index_name
, column_position
, column_name
FROM user_ind_columns
WHERE table_name = :table
ORDER BY index_name, column_order
References: