Question

我试图用mysql计算一个列的最多选择值，但我不知道如果这是可能的，或者如果我还需要使用php ...

所有值都是整数形式1到12的整数，它们是在前端进行的选择的id，而表（id：table）如下所示：

id | value_1 (int) | value_2 (int) | value_3 (int)

编辑：

有了这个，我可以获得最多选择的'value_1'列：

SELECT value_1, count( * ) total
FROM table
GROUP BY value_1
ORDER BY total DESC
LIMIT 1

如何在单个SQL语句中获取树列（value_1 | value_2 | value_3）中所有选中的最多值？

在重复的quiestion链接之后，我也尝试了这个，但它返回一个错误：

select value_1, count(*) total
from (
    select @r := if(total>@r,total,@r) maxcount, value_1, total
    from (select @r:=0) initvars, (
        select value_1, count(*) total
        from table
        group by value_1
    ) X ) Y
where total = @r

MYSQL ERROR : #1140 - Mixing of GROUP columns (MIN(),MAX(),COUNT(),...) with no GROUP columns is illegal if there is no GROUP BY clause

Answer 1

SELECT id, 
    COUNT(val1)As 'First Value', 
    COUNT(val2)As 'Second Value', 
    COUNT(val3)As 'Third Value'
FROM alez
GROUP BY id
ORDER BY id DESC

选择最高编号的ID将首先出现。然后，它们将根据最多选择的数字从最高到最低排序。

Answer 2

只是向读过这篇文章的用户澄清我设法做到了但是也使用了PHP。只用一次MYSQL句子就可以了，但我无法弄清楚如何做到这一点：

$array_sql = array("value_1", "value_2", "value_3");

//Loop
foreach($array_sql as $val){
    $SQL =  "
    SELECT $val, count( * ) total
    FROM table
    GROUP BY $val
    ORDER BY total DESC
    LIMIT 1
    ";

    ${'result_'.$val} = mysql_query($SQL) or die(mysql_error());//$result_mvp

}

//results for value_1
$row_1 = mysql_fetch_array($result_value_1);
$val1 = $row_1['total']; // Most selected option for value_1

//results for value_2
$row_2 = mysql_fetch_array($result_value_2);
$val2 = $row_2['total']; // Most selected option for value_2

//results for value_3
$row_3 = mysql_fetch_array($result_value_3);
$val3 = $row_3['total']; // Most selected option for value_3

计算列中的“最多选定值”

2 个答案: