Index position specification (index pos spec) 
The index position specification (
index pos spec ) is a syntax element in the following SQL statements: SELECT ORDERED statement (select ordered statement: searched) SELECT ORDERED statement (select ordered statement: positioned)Syntax
<index pos spec> ::= INDEX <column name> = <value spec>
| INDEXNAME <index name> VALUES (<value spec>,...)
Explanation
The column name in the index position specification must denote an indexed column.