如何从选定表的子集的联合选择中删除重复项

Question

我正在尝试按别名排序时删除重复的标题行

SELECT title,description,
                                (CASE WHEN title LIKE '%$searchterm%' then 10 else 0 END)+ 
                                (CASE WHEN keywords LIKE '%$searchterm%' then 5 else 0 END)+
                                (CASE WHEN description LIKE '%$searchterm%' then 3 else 0 END) 
                                AS priority
                                FROM searchengine 
                                WHERE
                                internalpage
                                HAVING priority > 0

for ($i=0;$i<=$spaces;$i++){
    $qrySearch .= "UNION SELECT title,description,
                                (CASE WHEN title LIKE '%$str_arr[$i]%' then 2 else 0 END)+ 
                                (CASE WHEN keywords LIKE '%$str_arr[$i]%' then 1 else 0 END)+
                                (CASE WHEN description LIKE '%$str_arr[$i]%' then 0.5 else 0 END) 
                                AS priority
                                FROM searchengine 
                                WHERE
                                internalpage
                                HAVING priority > 0
    $qrySearch .=   ORDER BY priority DESC

结果将按照最高优先级正确排序，但是在某些行中标题是相同的。 我想删除SQL中的那些行，我知道我以后很容易删除它们