Question

MySQL (simplified tables)

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)");

What I want to do now is:

a) If the id is included in table_2 OR table_3 it should be ranked higher than if it’s only present in table_1

b) If the id is included in table_2 AND table_3 it should be ranked even higher

So, the output should be:

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