如何从Php中的sql表中获取行位置

Question

I need the 'position (row)' from an SQL table using my PHP script. I tested my SQL statement and it worked fine. The output is correct.

My SQL statement:

SET @rownum = 0; 
SELECT position, name,cash FROM (SELECT name, cash, @rownum := @rownum + 1 AS position FROM 'my_DB'.'Cash' ORDER BY cash DESC ) AS t WHERE name = 'user44';

Output:

"position":44,"name":"user44","cash":"5600"

But if i put it in PHP:

$query="SET @rownum = 0; SELECT position, name,cash FROM (SELECT name, cash, @rownum := @rownum + 1 AS position FROM 'my_DB'.'Cash' ORDER BY cash DESC ) AS t WHERE name = 'user44';";

it shows me a errant query.

I also tried something like this:

$query="SELECT position, name,cash FROM (SELECT name, cash, @rownum := @rownum + 1 AS position FROM 'my_DB'.'Cash' ORDER BY cash DESC ) AS t WHERE name = 'user44';";

Output:

"position":null,"name":"user44","cash":"5600"

Thanks to VolkerK, i solved that Problem with:

$query = "SET @rownum =0;"; $result = mysql_query($query,$link) or die('Errant query: '.$query); $query="SELECT position, name,cash FROM (SELECT name, cash, @rownum := @rownum + 1 AS position FROM 'my_DB'.'HSCash' ORDER BY cash DESC ) AS t WHERE name = 'user44'"; $result = mysql_query($query,$link) or die('Errant query: '.$query);

Answer 1

I understand better now.

The trick is not to get the position, it's to get the number of people that have a better score than the user.

SQL:

// Get how much cash the user make
SELECT cash
FROM mydb.cash
WHERE name = :name;

// Get how many people did better + 1
SELECT COUNT(*)+1
FROM mydb.cash
WHERE cash > :cash

The contatenated query is more complicated, but didn't need to order the whole table, and looks like

SELECT position, name, cash
FROM mydb.cash
JOIN (
    SELECT COUNT(*)+1 AS position
    FROM mydb.cash
    WHERE cash > (
        SELECT cash
        FROM mydb.cash
        WHERE name = :name
    )
)
WHERE name = :name

Or, to limit the join by filtering before joining, like :

SELECT position, name, cash
FROM (
    SELECT name, cash
    FROM mydb.cash
    WHERE name = :name
)
JOIN (
    SELECT COUNT(*)+1 AS position
    FROM mydb.cash
    WHERE cash > (
        SELECT cash
        FROM mydb.cash
        WHERE name = :name
    )
)