(PECL sphinx >= 0.1.0)
SphinxClient::setGroupDistinct — Set attribute name for per-group distinct values count calculations
$attribute
)
Sets attribute name for per-group distinct values count calculations. Only
available for grouping queries. For each group, all values of
attribute will be stored, then the amount of
distinct values will be calculated and returned to the client. This feature
is similar to COUNT(DISTINCT) clause in SQL.
attributeA string containing group-by attribute name.
成功时返回 TRUE， 或者在失败时返回 FALSE。