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mysql> SELECT node.name FROM nested_category AS node, nested_category AS parent WHERE node.lft BETWEEN parent.lft AND parent.rgt AND parent.name = ‘ELECTRONICS‘ ORDER BY node.lft; +----------------------+ | name | +----------------------+ | ELECTRONICS | | TELEVISIONS | | TUBE | | LCD | | PLASMA | | PORTABLE ELECTRONICS | | MP3 PLAYERS | | FLASH | | CD PLAYERS | | 2 WAY RADIOS | +----------------------+ 10 rows in set mysql> SELECT name FROM nested_category WHERE rgt = lft + 1; +--------------+ | name | +--------------+ | TUBE | | LCD | | PLASMA | | FLASH | | CD PLAYERS | | 2 WAY RADIOS | +--------------+ 6 rows in set mysql> SELECT parent.name FROM nested_category AS node, nested_category AS parent WHERE node.lft BETWEEN parent.lft AND parent.rgt AND node.name = ‘FLASH‘ ORDER BY parent.lft ASC; +----------------------+ | name | +----------------------+ | ELECTRONICS | | PORTABLE ELECTRONICS | | MP3 PLAYERS | | FLASH | +----------------------+ 4 rows in set mysql> SELECT node.name, (COUNT(parent.name) - 1) AS depth FROM nested_category AS node, nested_category AS parent WHERE node.lft BETWEEN parent.lft AND parent.rgt GROUP BY node.name ORDER BY node.lft; +----------------------+-------+ | name | depth | +----------------------+-------+ | ELECTRONICS | 0 | | TELEVISIONS | 1 | | TUBE | 2 | | LCD | 2 | | PLASMA | 2 | | PORTABLE ELECTRONICS | 1 | | MP3 PLAYERS | 2 | | FLASH | 3 | | CD PLAYERS | 2 | | 2 WAY RADIOS | 2 | +----------------------+-------+ 10 rows in set mysql> SELECT CONCAT( REPEAT(‘|-- ‘, COUNT(parent.name) - 1), node.name) AS name FROM nested_category AS node, nested_category AS parent WHERE node.lft BETWEEN parent.lft AND parent.rgt GROUP BY node.name ORDER BY node.lft; +-------------------------+ | name | +-------------------------+ | ELECTRONICS | | |--TELEVISIONS | | |--|--TUBE | | |--|--LCD | | |--|--PLASMA | | |--PORTABLE ELECTRONICS | | |--|--MP3 PLAYERS | | |--|--|--FLASH | | |--|--CD PLAYERS | | |--|--2 WAY RADIOS | +-------------------------+ 10 rows in set mysql> SELECT node.name, (COUNT(parent.name) - (sub_tree.depth + 1)) AS depth FROM nested_category AS node, nested_category AS parent, nested_category AS sub_parent, ( SELECT node.name, (COUNT(parent.name) - 1) AS depth FROM nested_category AS node, nested_category AS parent WHERE node.lft BETWEEN parent.lft AND parent.rgt AND node.name = ‘PORTABLE ELECTRONICS‘ GROUP BY node.name ORDER BY node.lft )AS sub_tree WHERE node.lft BETWEEN parent.lft AND parent.rgt AND node.lft BETWEEN sub_parent.lft AND sub_parent.rgt AND sub_parent.name = sub_tree.name GROUP BY node.name ORDER BY node.lft; +----------------------+-------+ | name | depth | +----------------------+-------+ | PORTABLE ELECTRONICS | 0 | | MP3 PLAYERS | 1 | | FLASH | 2 | | CD PLAYERS | 1 | | 2 WAY RADIOS | 1 | +----------------------+-------+ 5 rows in set mysql> SELECT node.name, (COUNT(parent.name) - (sub_tree.depth + 1)) AS depth FROM nested_category AS node, nested_category AS parent, nested_category AS sub_parent, ( SELECT node.name, (COUNT(parent.name) - 1) AS depth FROM nested_category AS node, nested_category AS parent WHERE node.lft BETWEEN parent.lft AND parent.rgt AND node.name = ‘PORTABLE ELECTRONICS‘ GROUP BY node.name ORDER BY node.lft )AS sub_tree WHERE node.lft BETWEEN parent.lft AND parent.rgt AND node.lft BETWEEN sub_parent.lft AND sub_parent.rgt AND sub_parent.name = sub_tree.name GROUP BY node.name ORDER BY node.lft; +----------------------+-------+ | name | depth | +----------------------+-------+ | PORTABLE ELECTRONICS | 0 | | MP3 PLAYERS | 1 | | FLASH | 2 | | CD PLAYERS | 1 | | 2 WAY RADIOS | 1 | +----------------------+-------+ 5 rows in set mysql> SELECT node.name, (COUNT(parent.name) - (sub_tree.depth + 1)) AS depth FROM nested_category AS node, nested_category AS parent, nested_category AS sub_parent, ( SELECT node.name, (COUNT(parent.name) - 1) AS depth FROM nested_category AS node, nested_category AS parent WHERE node.lft BETWEEN parent.lft AND parent.rgt AND node.name = ‘PORTABLE ELECTRONICS‘ GROUP BY node.name ORDER BY node.lft )AS sub_tree WHERE node.lft BETWEEN parent.lft AND parent.rgt AND node.lft BETWEEN sub_parent.lft AND sub_parent.rgt AND sub_parent.name = sub_tree.name GROUP BY node.name HAVING depth <= 1 ORDER BY node.lft; +----------------------+-------+ | name | depth | +----------------------+-------+ | PORTABLE ELECTRONICS | 0 | | MP3 PLAYERS | 1 | | CD PLAYERS | 1 | | 2 WAY RADIOS | 1 | +----------------------+-------+ 4 rows in set mysql> SELECT node.name, (COUNT(parent.name) - (sub_tree.depth + 1)) AS depth FROM nested_category AS node, nested_category AS parent, nested_category AS sub_parent, ( SELECT node.name, (COUNT(parent.name) - 1) AS depth FROM nested_category AS node, nested_category AS parent WHERE node.lft BETWEEN parent.lft AND parent.rgt AND node.name = ‘PORTABLE ELECTRONICS‘ GROUP BY node.name ORDER BY node.lft )AS sub_tree WHERE node.lft BETWEEN parent.lft AND parent.rgt AND node.lft BETWEEN sub_parent.lft AND sub_parent.rgt AND sub_parent.name = sub_tree.name GROUP BY node.name HAVING depth = 1 ORDER BY node.lft; +--------------+-------+ | name | depth | +--------------+-------+ | MP3 PLAYERS | 1 | | CD PLAYERS | 1 | | 2 WAY RADIOS | 1 | +--------------+-------+ 3 rows in set mysql> CREATE TABLE product ( product_id INT AUTO_INCREMENT PRIMARY KEY, name VARCHAR(40), category_id INT NOT NULL ); INSERT INTO product(name, category_id) VALUES(‘20" TV‘,3),(‘36" TV‘,3), (‘Super-LCD 42"‘,4),(‘Ultra-Plasma 62"‘,5),(‘Value Plasma 38"‘,5), (‘Power-MP3 5gb‘,7),(‘Super-Player 1gb‘,8),(‘Porta CD‘,9),(‘CD To go!‘,9), (‘Family Talk 360‘,10); Query OK, 0 rows affected Query OK, 10 rows affected Records: 10 Duplicates: 0 Warnings: 0 mysql> SELECT parent.name, COUNT(product.name) FROM nested_category AS node , nested_category AS parent, product WHERE node.lft BETWEEN parent.lft AND parent.rgt AND node.category_id = product.category_id GROUP BY parent.name ORDER BY node.lft; +----------------------+---------------------+ | name | COUNT(product.name) | +----------------------+---------------------+ | ELECTRONICS | 10 | | TELEVISIONS | 5 | | TUBE | 2 | | LCD | 1 | | PLASMA | 2 | | PORTABLE ELECTRONICS | 5 | | MP3 PLAYERS | 2 | | FLASH | 1 | | CD PLAYERS | 2 | | 2 WAY RADIOS | 1 | +----------------------+---------------------+ 10 rows in set mysql> LOCK TABLE nested_category WRITE; SELECT @myRight := rgt FROM nested_category WHERE name = ‘TELEVISIONS‘; UPDATE nested_category SET rgt = rgt + 2 WHERE rgt > @myRight; UPDATE nested_category SET lft = lft + 2 WHERE lft > @myRight; INSERT INTO nested_category(name, lft, rgt) VALUES(‘GAME CONSOLES‘, @myRight + 1, @myRight + 2); UNLOCK TABLES; Query OK, 0 rows affected +-----------------+ | @myRight := rgt | +-----------------+ | 9 | +-----------------+ 1 row in set Query OK, 6 rows affected Rows matched: 6 Changed: 6 Warnings: 0 Query OK, 5 rows affected Rows matched: 5 Changed: 5 Warnings: 0 Query OK, 1 row affected Query OK, 0 rows affected mysql> SELECT CONCAT( REPEAT(‘|--‘, COUNT(parent.name) - 1), node.name) AS name FROM nested_category AS node, nested_category AS parent WHERE node.lft BETWEEN parent.lft AND parent.rgt GROUP BY node.name ORDER BY node.lft; +-------------------------+ | name | +-------------------------+ | ELECTRONICS | | |--TELEVISIONS | | |--|--TUBE | | |--|--LCD | | |--|--PLASMA | | |--GAME CONSOLES | | |--PORTABLE ELECTRONICS | | |--|--MP3 PLAYERS | | |--|--|--FLASH | | |--|--CD PLAYERS | | |--|--2 WAY RADIOS | +-------------------------+ 11 rows in set mysql> LOCK TABLE nested_category WRITE; SELECT @myLeft := lft FROM nested_category WHERE name = ‘2 WAY RADIOS‘; UPDATE nested_category SET rgt = rgt + 2 WHERE rgt > @myLeft; UPDATE nested_category SET lft = lft + 2 WHERE lft > @myLeft; INSERT INTO nested_category(name, lft, rgt) VALUES(‘FRS‘, @myLeft + 1, @myLeft + 2); UNLOCK TABLES; Query OK, 0 rows affected +----------------+ | @myLeft := lft | +----------------+ | 19 | +----------------+ 1 row in set Query OK, 3 rows affected Rows matched: 3 Changed: 3 Warnings: 0 Query OK, 0 rows affected Rows matched: 0 Changed: 0 Warnings: 0 Query OK, 1 row affected Query OK, 0 rows affected mysql> SELECT CONCAT( REPEAT(‘|--‘, COUNT(parent.name) - 1), node.name) AS name FROM nested_category AS node, nested_category AS parent WHERE node.lft BETWEEN parent.lft AND parent.rgt GROUP BY node.name ORDER BY node.lft; +-------------------------+ | name | +-------------------------+ | ELECTRONICS | | |--TELEVISIONS | | |--|--TUBE | | |--|--LCD | | |--|--PLASMA | | |--GAME CONSOLES | | |--PORTABLE ELECTRONICS | | |--|--MP3 PLAYERS | | |--|--|--FLASH | | |--|--CD PLAYERS | | |--|--2 WAY RADIOS | | |--|--|--FRS | +-------------------------+ 12 rows in set mysql> LOCK TABLE nested_category WRITE; SELECT @myLeft := lft, @myRight := rgt, @myWidth := rgt - lft + 1 FROM nested_category WHERE name = ‘GAME CONSOLES‘; DELETE FROM nested_category WHERE lft BETWEEN @myLeft AND @myRight; UPDATE nested_category SET rgt = rgt - @myWidth WHERE rgt > @myRight; UPDATE nested_category SET lft = lft - @myWidth WHERE lft > @myRight; UNLOCK TABLES; Query OK, 0 rows affected +----------------+-----------------+---------------------------+ | @myLeft := lft | @myRight := rgt | @myWidth := rgt - lft + 1 | +----------------+-----------------+---------------------------+ | 10 | 11 | 2 | +----------------+-----------------+---------------------------+ 1 row in set Query OK, 1 row affected Query OK, 7 rows affected Rows matched: 7 Changed: 7 Warnings: 0 Query OK, 6 rows affected Rows matched: 6 Changed: 6 Warnings: 0 Query OK, 0 rows affected mysql> SELECT CONCAT( REPEAT(‘|--‘, COUNT(parent.name) - 1), node.name) AS name FROM nested_category AS node, nested_category AS parent WHERE node.lft BETWEEN parent.lft AND parent.rgt GROUP BY node.name ORDER BY node.lft; +-------------------------+ | name | +-------------------------+ | ELECTRONICS | | |--TELEVISIONS | | |--|--TUBE | | |--|--LCD | | |--|--PLASMA | | |--PORTABLE ELECTRONICS | | |--|--MP3 PLAYERS | | |--|--|--FLASH | | |--|--CD PLAYERS | | |--|--2 WAY RADIOS | | |--|--|--FRS | +-------------------------+ 11 rows in set mysql> LOCK TABLE nested_category WRITE; SELECT @myLeft := lft, @myRight := rgt, @myWidth := rgt - lft + 1 FROM nested_category WHERE name = ‘MP3 PLAYERS‘; DELETE FROM nested_category WHERE lft BETWEEN @myLeft AND @myRight; UPDATE nested_category SET rgt = rgt - @myWidth WHERE rgt > @myRight; UPDATE nested_category SET lft = lft - @myWidth WHERE lft > @myRight; UNLOCK TABLES; Query OK, 0 rows affected +----------------+-----------------+---------------------------+ | @myLeft := lft | @myRight := rgt | @myWidth := rgt - lft + 1 | +----------------+-----------------+---------------------------+ | 11 | 14 | 4 | +----------------+-----------------+---------------------------+ 1 row in set Query OK, 2 rows affected Query OK, 5 rows affected Rows matched: 5 Changed: 5 Warnings: 0 Query OK, 3 rows affected Rows matched: 3 Changed: 3 Warnings: 0 Query OK, 0 rows affected mysql> SELECT CONCAT( REPEAT(‘|--‘, COUNT(parent.name) - 1), node.name) AS name FROM nested_category AS node, nested_category AS parent WHERE node.lft BETWEEN parent.lft AND parent.rgt GROUP BY node.name ORDER BY node.lft; +-------------------------+ | name | +-------------------------+ | ELECTRONICS | | |--TELEVISIONS | | |--|--TUBE | | |--|--LCD | | |--|--PLASMA | | |--PORTABLE ELECTRONICS | | |--|--CD PLAYERS | | |--|--2 WAY RADIOS | | |--|--|--FRS | +-------------------------+ 9 rows in set mysql> LOCK TABLE nested_category WRITE; SELECT @myLeft := lft, @myRight := rgt, @myWidth := rgt - lft + 1 FROM nested_category WHERE name = ‘PORTABLE ELECTRONICS‘; DELETE FROM nested_category WHERE lft = @myLeft; UPDATE nested_category SET rgt = rgt - 1, lft = lft - 1 WHERE lft BETWEEN @myLeft AND @myRight; UPDATE nested_category SET rgt = rgt - 2 WHERE rgt > @myRight; UPDATE nested_category SET lft = lft - 2 WHERE lft > @myRight; UNLOCK TABLES; Query OK, 0 rows affected +----------------+-----------------+---------------------------+ | @myLeft := lft | @myRight := rgt | @myWidth := rgt - lft + 1 | +----------------+-----------------+---------------------------+ | 10 | 17 | 8 | +----------------+-----------------+---------------------------+ 1 row in set Query OK, 1 row affected Query OK, 3 rows affected Rows matched: 3 Changed: 3 Warnings: 0 Query OK, 1 row affected Rows matched: 1 Changed: 1 Warnings: 0 Query OK, 0 rows affected Rows matched: 0 Changed: 0 Warnings: 0 Query OK, 0 rows affected mysql> SELECT CONCAT( REPEAT(‘|--‘, COUNT(parent.name) - 1), node.name) AS name FROM nested_category AS node, nested_category AS parent WHERE node.lft BETWEEN parent.lft AND parent.rgt GROUP BY node.name ORDER BY node.lft; +-----------------+ | name | +-----------------+ | ELECTRONICS | | |--TELEVISIONS | | |--|--TUBE | | |--|--LCD | | |--|--PLASMA | | |--CD PLAYERS | | |--2 WAY RADIOS | | |--|--FRS | +-----------------+ 8 rows in set mysql> SELECT @myLeft := lft, @myRight := rgt, @myWidth := rgt - lft + 1 FROM nested_category WHERE name = ‘LCD‘; +----------------+-----------------+---------------------------+ | @myLeft := lft | @myRight := rgt | @myWidth := rgt - lft + 1 | +----------------+-----------------+---------------------------+ | 5 | 6 | 2 | +----------------+-----------------+---------------------------+ 1 row in set mysql>
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原文地址：http://my.oschina.net/springleng/blog/393658
