DWS provides functions and operators that can be used to manipulate queries that are already in tsquery type.
Returns the AND-combination of the two given tsqueries.
Returns the OR-combination of the two given tsqueries.
Returns the negation (NOT) of the given tsquery.
Returns the number of nodes (lexemes plus operators) in a tsquery. This function is useful to determine if the query is meaningful (returns > 0), or contains only stop words (returns 0). For example:
SELECT numnode(plainto_tsquery('the any')); NOTICE: text-search query contains only stop words or doesn't contain lexemes, ignored CONTEXT: referenced column: numnode numnode --------- 0 SELECT numnode('foo & bar'::tsquery); numnode --------- 3
Returns the portion of a tsquery that can be used for searching an index. This function is useful for detecting unindexable queries, for example those containing only stop words or only negated terms. For example:
SELECT querytree(to_tsquery('!defined')); querytree ----------- T (1 row)