Question

我需要从表格行中删除重复项。合并3个数字并生成所有可能的组合，以.html格式发布（如果所有数字都不同，则为6）数字必须各有6个数字，如： 123,234等....如果一个数字与另一个数字相同，减少组合的数量，像112。我做了什么，直到现在...... 隔离数字并将其存储在一行：

        $cc=GetRow("SELECT numbers FROM table");
        $n1=substr($cc, 0, 1);
        $n2=substr($cc, 1, 1);
        $n3=substr($cc, 2, 1);

        //scrambling the numbers
        $n1n2n3=$n1.$n2.$n3; //123 number stored
        $n1n3n2=$n1.$n3.$n2; //132 number stored
        $n2n1n3=$n2.$n1.$n3; //213 number stored
        $n2n3n1=$n2.$n3.$n1; //231 number stored
        $n3n1n2=$n3.$n1.$n2; //312 number stored
        $n3n2n1=$n3.$n2.$n1; //321 number stored

        $sql = sqlQuery("UPDATE table SET cc_concat = CONCAT_WS(',', '$n1n2n3', '$n1n3n2','$n2n1n3','$n2n3n1','$n3n1n2','$n3n2n1')");

        But here´s the problem:
        if the number is 112 will generate duplicates, only 3 are uniques:
        $n1n2n3=$n1.$n2.$n3; //112 number stored
        $n1n3n2=$n1.$n3.$n2; //121 number stored
        $n2n1n3=$n2.$n1.$n3; //112 number stored
        $n2n3n1=$n2.$n3.$n1; //121 number stored
        $n3n1n2=$n3.$n1.$n2; //211 number stored
        $n3n2n1=$n3.$n2.$n1; //211 number stored

        Is there a way to update the table without the duplicates? or remove the duplicates
        after update?

谢谢！

Answer 1

您可以使用数组来存储组合并利用in_array（）函数来确保您不会有重复项：

$combinations = array();
if ( !in_array( $n1n2n3, $combinations ) ) $combinations[] = $n1n2n3;
if ( !in_array( $n1n3n2, $combinations ) ) $combinations[] = $n1n3n2;
// Do the same for the rest

// Then you could easily concatenate the result set from PHP.
$cc_concat = implode( ',', $combinations );

// Finally update the database.
$sql = sqlQuery("UPDATE table SET cc_concat = '{$cc_concat}' ");

这样的事情应该可以解决问题。

此外，您可能更喜欢使用算法从三位数组中为您生成组合。对于这样的算法，你可以检查这个线程： Get all permutations of a PHP array?

Concat唯一或删除重复的字符串php / mysql

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