CREATE [UNIQUE] INDEX maxamount ON Sales(amount) TABLESPACE tab_space;where
UNIQUE means that the values in the indexed columns must be unique.
index_name is the name of the index.
table_name is a database table.
column_name is the indexed column. You can create an index on multiple columns
(these kind of index is known as a composite index).
tab_space is the tablespace for the index. If you don’t provide a tablespace, the index
is stored in the user’s default tablespace.
For performance reasons, you should typically store indexes in a
different tablespace from tables.