2

我正在将 MySql 与 PHP 一起使用，并将我的所有数据放在这样的表中：

"id"    "name"         "description"               "level"  "parent"    "country"   "maxLevel"
"1"     "Kitchenware"   "Kitchenware description"   "1"       "0"         "US"        "0"
"2"     "Knives"        "All our knives"            "2"       "1"         "US"        "0"
"3"     "Butter Knives" "All Butter Knives"         "3"       "2"         "US"        "0"
"4"     "Cut em all"    "Cut em all"                "4"       "3"         "US"        "0"
"5"     "Cull em all"   "Cull em all"               "4"       "3"         "US"        "0"
"6"     "Smear em all"  "Smear em all"              "4"       "3"         "US"        "0"
"7"     "Meat Knives"   "All Meat Knives"           "3"       "2"         "US"        "0"
"8"     "Cut em meat"   "Cut em meat"               "4"       "7"         "US"        "0"
"9"     "Cull em meat"  "Cull em meat"              "4"       "7"         "US"        "0"
"10"    "Smear em meat" "Smear em meat"             "4"       "7"         "US"        "0"

由此，如果我有例如：id = 10，sql将如何显示项目的层次结构？

因此对于 id = 10，层次结构将是：

Kitchenware > Knives > Meat Knives > Smear em meat

对于 id=7，层次结构将是：

Kitchenware > Knives > Meat Knives

对于 id=4，层次结构将是

Kitchenware > Knives > Butter Knives > Cut em all

等等。知道如何构造 sql 来实现这一点吗？

4

2 回答 2

4

试试这个存储过程

CREATE PROCEDURE updatePath(in itemId int)
BEGIN
    DECLARE cnt int default 0;
    CREATE temporary table tmpTable 
    (
       `id` int, `name` varchar(15), `parent` int, path varchar(500)  
     )engine=memory select id, name, parent, name AS 'Path' from tbl where id = itemId;
    select parent into cnt from tmpTable;

    while cnt <> 0 do
       Update tmpTable tt, tbl t set tt.parent = t.parent, 
              tt.path = concat(t.name, ' > ', tt.path)
       WHERE tt.parent = t.id;
       select parent into cnt from tmpTable;
    end while;
    select * from tmpTable;
    drop table tmpTable;
END//

查询 1：

call updatePath(10)

SQL 小提琴：

| ID |            NAME | PARENT |                                                       PATH |
----------------------------------------------------------------------------------------------
| 10 | "Smear em meat" |      0 | "Kitchenware" > "Knives" > "Meat Knives" > "Smear em meat" |

希望这可以帮助

于 2013-05-06T04:38:50.143 回答
3

尝试这个：

我会像这样设置一个 SQL 表：

CREATE TABLE `table` (
    `id` int(11),
    `name` varchar(32),
    `description` varchar(32),
    `level` int(11),
    `parent` int(11),
    `country` varchar(32),
    `maxLevel` int(11)
);

这是要插入的测试数据：

INSERT INTO `table` VALUES
("1",     "Kitchenware",   "Kitchenware description",   "1",       "0",         "US",        "0"),
("2",     "Knives",        "All our knives",            "2",       "1",         "US",        "0"),
("3",     "Butter Knives", "All Butter Knives",         "3",       "2",         "US",        "0"),
("4",     "Cut em all",    "Cut em all",                "4",       "3",         "US",        "0"),
("5",     "Cull em all",   "Cull em all",               "4",       "3",         "US",        "0"),
("6",     "Smear em all",  "Smear em all",              "4",       "3",         "US",        "0"),
("7",     "Meat Knives",   "All Meat Knives",           "3",       "2",         "US",        "0"),
("8",     "Cut em meat",   "Cut em meat",               "4",       "7",         "US",        "0"),
("9",     "Cull em meat",  "Cull em meat",              "4",       "7",         "US",        "0"),
("10",    "Smear em meat", "Smear em meat",             "4",       "7",         "US",        "0");

最后，这是要测试的代码：

<?php
$mysqli=new Mysqli("127.0.0.1","root","DATABASE_PASSWORD","DATABASE_NAME");

function getHierarchy($id) {
    global $mysqli;

    $final="";

    $query="SELECT `name`,`parent` FROM `table` WHERE `id`=";
    $result=$mysqli->query($query.$id);
    $result=$result->fetch_assoc();

    while($result['parent']!=0) {
        $result=$mysqli->query($query.$id);
        $result=$result->fetch_assoc();
        $id=$result['parent'];
        $final=$result["name"]." > ".$final;
    }

    $final=substr($final,0,-3);
    return $final;
}

echo getHierarchy(10)."<br>\n";
echo getHierarchy(7)."<br>\n";
echo getHierarchy(4)."<br>\n";

$mysqli->close();
?>

打印出来：

Kitchenware > Knives > Meat Knives > Smear em meat
Kitchenware > Knives > Meat Knives
Kitchenware > Knives > Butter Knives > Cut em all
于 2013-05-06T03:58:32.377 回答