Order - If the select
statement containing the contains predicate does not specify an
exact match of the primary key of the table having the contains
predicate, then the contains predicate will be the 'driving'
condition, meaning that rows come in ascending or descending order
of the free text document ID.
The DESCENDING keyword
specifies the descending order of the free text index document ID
and has nothing to do with a possible ORDER BY of the enclosing
statement. Even if there is an ORDER BY in the enclosing statement
the DESCENDING keyword of contains has an effect in the
interpretation of the STRT_ID and END_ID contains options.
If there is a full equality match of the primary key of the
table, this will be the driving predicate and contains will only be
used to check if the text expression matches the single row
identified by the full match of the primary key.
The contains predicate may not appear outside of a select
statement and may only reference a column for which a free text
index has been declared. The first argument must be a column for
which there is such an index. The text expression may be variable
and computed, although it must be constant during the evaluation of
the select statement containing it.
The contains predicate must be a part of the top level AND of
the WHERE clause of the containing select. It may not for example
be a term of an OR predicate in the select but can be AND'ed with
an OR expression.