Question

MySQL（简化表格）

TABLE_1

+----+-------+
| id | title |
+----+-------+
| 1  | test  |
+----+-------+
| 2  | test  |
+----+-------+
| 3  | test  |
+----+-------+

TABLE_2

+----+
| id |
+----+
| 1  |
+----+

TABLE_3

+----+
| id |
+----+
| 1  |
+----+
| 3  |
+----+

PHP

$a = mysql_query("SELECT t1.id FROM table_1 AS t1 WHERE MATCH(t1.title) AGAINST ('test' IN BOOLEAN MODE)");

我现在想做的是：

a）如果id或table_2中包含table_3，则其排名应高于table_1

中仅存在的排名

b）如果id和table_2中包含table_3，则排名应该更高

所以，输出应该是：

1, 3, 2

Answer 1

select table_1.id, 
  (case
  when max(table_2.id) is not null AND max(table_3.id) is not null then 0
  when max(table_2.id) is not null OR max(table_3.id) is not null then 1
  else 2
  end) rank
from table_1 left outer join table_2 on
   table_1.id = table_2.id left outer join table_3 on
   table_1.id = table_3.id
group by table_1.id
order by rank

Answer 2

SELECT a.id 
FROM table_1 a
LEFT JOIN table_2 b ON b.id = a.id
LEFT JOIN table_3 c ON c.id = a.id
ORDER BY
    b.id IS NOT NULL AND c.id IS NOT NULL DESC,
    b.id IS NOT NULL OR c.id IS NOT NULL DESC

当多个条目具有相同的优先级时，您可以对后续的排序进行广告

MySQL：如何根据它们是否也存在于其他表中来对结果进行排序？

2 个答案: