Question

When i perform this query:

select id as current from events where date = '{$result['date']}'
union all
(select id as previous from events where date < '{$result['date']}' order by date desc limit 1)
union all
(select id as next from events where date > '{$result['date']}' order by date asc limit 1)

it selects the ID where the date is $result['date], the date below that, and the date above that.

So in my php code i need an array like so:

Array
(
    [0] => Array
    (
        [current] => 6
    )

    [1] => Array
    (
        [previous] => 5
    )

    [2] => Array
    (
        [next] => 7
    )

)

however, the array comes out like:

Array
(
    [0] => Array
    (
        [current] => 6
    )

    [1] => Array
    (
        [current] => 5
    )

    [2] => Array
    (
        [current] => 7
    )

)

I need the assoc array to depict the right keys!

Even though in my SQL i do

select id as current
select id as previous
select id as next

they all come out as current???

any ideas?

Answer 1

The reason why the column is the same name is because when you UNION two or more queries, the name of the column(s) in the topmost query are always the names displayed in the final result, regardless of the column names in subsequent queries (they are essentially ignored).

MySQL Union Syntax

“The column names from the first SELECT statement are used as the column names for the results returned.”

---

Instead, why not get the id’s in separate columns in one query?

SELECT a.id AS current, prev.id AS previous, next.id AS next
FROM events a
CROSS JOIN 
(
    SELECT id FROM events 
    WHERE date < '{$result['date']}' 
    ORDER BY date DESC 
    LIMIT 1
) prev
CROSS JOIN 
(
    SELECT id
    FROM events 
    WHERE date > '{$result['date']}' 
    ORDER BY date 
    LIMIT 1
) next
WHERE a.date = '{$result['date']}'

Which would give you something like:

Array
(
    [0] => Array
    (
        [current] => 6
        [previous] => 5
        [next] => 7
    )
)