CODEWITHSUNDEEP
phpmysqlsqlhierarchical-data
Norman
Norman

Reputation: 6365

Retrieve hierarchy from a table like this

I'm using MySql with PHP and have all my data in a table like this:

"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"

From this, If I had for eg: id = 10, how would the sql be to display the hierarchy for an item?

So for id = 10, the hierarchy would be:

Kitchenware > Knives > Meat Knives > Smear em meat

For id=7 the hierrchy would be:

Kitchenware > Knives > Meat Knives

For id=4 the hierarchy would be

Kitchenware > Knives > Butter Knives > Cut em all

And so on. Any idea how to structure the sql to achieve this?

Upvotes: 2

Views: 464

Answers (2)

Meherzad
Meherzad

Reputation: 8563

Try this stored procedure

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//

Query 1:

call updatePath(10)

SQL FIDDLE:

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

Hope this helps

Upvotes: 4

Dave Chen
Dave Chen

Reputation: 10975

Try this:

I would setup a SQL table like this:

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

Here is the test data to insert:

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");

Finally, here is the code to test:

<?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();
?>

Prints out:

Kitchenware > Knives > Meat Knives > Smear em meat
Kitchenware > Knives > Meat Knives
Kitchenware > Knives > Butter Knives > Cut em all

Upvotes: 3

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