Question

I have a table with two columns [id, value] both numeric.

In this example:

[ id, value ]
[ 1,  6     ]
[ 2,  4     ]
[ 3,  10    ]
[ 4,  2     ]
[ 5,  7     ]
[ 6,  3     ]

For a given id I’d like to retrieve the top 3 id’s (those with highest value), their top position and if the given id is not in the top 3, also get its position, id and value:

Example 1: ask_id = 5 Return:

[ position, id, value ]
[ 1,        3,  10    ]
[ 2,        5,  7     ]
[ 3,        1,  6     ]

Example 2: ask_id = 4. Return:

[ position, id, value ]
[ 1,        3,  10    ]
[ 2,        5,  7     ]
[ 3,        1,  6     ]
[ 6,        4,  2     ]

So the important points are:

• How to get for the position column?
• How to get the additional row if possible (anyway there’s no problem if I need two queries)?

Answer 1

select t2.pos, t1.id, t1.value 
from test as t1
inner join
(select id, value, @pos:=if(@pos is null, 0, @pos)+1 as pos 
 from test order by value desc) as t2
on t1.id=t2.id
where t2.pos<=3 or t2.id={$ask_id}
order by t2.pos;