+ $search_query = trim($search_query);
+ $search_query = str_replace("'", " ", $search_query);
+
+ // Search word fragments.
+ // sfc = search fragment condition
+ $sfc = "( ";
+ // sfr = serach fragment relevation
+ $sfr = "( ";
+ $sep = ' +-*<>()~"';
+ $fragm = strtok($search_query, $sep);
+ while ($fragm !== FALSE)
+ {
+ $sfc .= "(title LIKE '%$fragm%'
+ OR description LIKE '%$fragm%'
+ OR tags LIKE '%$fragm%') OR ";
+
+ // Frament relevations are half of boolean relevations such
+ // that they will appear at the end of the results.
+ $sfr .= "0.25 * (title LIKE '%$fragm%')
+ + 0.1 * (description LIKE '%$fragm%')
+ + 0.15 * (tags LIKE '%$fragm%') + ";
+
+ $fragm = strtok($sep);
+ }
+ $sfc = substr($sfc, 0, -4) . " )";
+ $sfr = substr($sfr, 0, -3) . " )";
+
+ if (! $this->is_advanced_search_query($search_query))
+ {
+ $search_cond = "MATCH (title, description, tags)
+ AGAINST ('$search_query') OR $sfc";
+ $relevance = "( MATCH (title, description, tags)
+ AGAINST ('$search_query') + $sfr ) AS relevance";
+ }
+ // boolean mode
+ else
+ {
+ $against = "AGAINST ('$search_query' IN BOOLEAN MODE)";
+ $search_cond = "( MATCH (title, description, tags)
+ $against) OR $sfc";
+ $relevance = "( 0.5 * (MATCH(title) $against)
+ + 0.3 * (MATCH(tags) $against)
+ + 0.2 * (MATCH(description) $against)
+ + $sfr) AS relevance";
+ }
+