關于多級別菜單欄或者權限系統中部門上下級的樹形遍歷，oracle中有connect by來實現，mysql沒有這樣的便捷途徑，所以MySQL遍歷數據表是我們經常會遇到的頭痛問題，下面通過存儲過程來實現。
1，建立測試表和數據：
DROP TABLE IF EXISTS csdn.channel; CREATE TABLE csdn.channel ( id INT(11) NOT NULL AUTO_INCREMENT, cname VARCHAR(200) DEFAULT NULL, parent_id INT(11) DEFAULT NULL, PRIMARY KEY (id) ) ENGINE=INNODB DEFAULT CHARSET=utf8; INSERT INTO channel(id,cname,parent_id) VALUES (13,'首頁',-1), (14,'TV580',-1), (15,'生活580',-1), (16,'左上幻燈片',13), (17,'幫忙',14), (18,'欄目簡介',17); DROP TABLE IF EXISTS channel;
2，利用臨時表和遞歸過程實現樹的遍歷（mysql的UDF不能遞歸調用）：
2.1，從某節點向下遍歷子節點，遞歸生成臨時表數據
-- pro_cre_childlistDROP PROCEDURE IF EXISTS csdn.pro_cre_childlistCREATE PROCEDURE csdn.pro_cre_childlist(IN rootId INT,IN nDepth INT)DECLARE done INT DEFAULT 0;DECLARE b INT;DECLARE cur1 CURSOR FOR SELECT id FROM channel WHERE parent_id=rootId;DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = 1;SET max_sp_recursion_depth=12;INSERT INTO tmpLst VALUES (NULL,rootId,nDepth); OPEN cur1; FETCH cur1 INTO b; WHILE done=0 DO CALL pro_cre_childlist(b,nDepth+1); FETCH cur1 INTO b; END WHILE; CLOSE cur1;
2.2，從某節點向上追溯根節點，遞歸生成臨時表數據
-- pro_cre_parentlistDROP PROCEDURE IF EXISTS csdn.pro_cre_parentlistCREATE PROCEDURE csdn.pro_cre_parentlist(IN rootId INT,IN nDepth INT) BEGIN DECLARE done INT DEFAULT 0; DECLARE b INT; DECLARE cur1 CURSOR FOR SELECT parent_id FROM channel WHERE id=rootId; DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = 1; SET max_sp_recursion_depth=12; INSERT INTO tmpLst VALUES (NULL,rootId,nDepth); OPEN cur1; FETCH cur1 INTO b; WHILE done=0 DO CALL pro_cre_parentlist(b,nDepth+1); FETCH cur1 INTO b; END WHILE; CLOSE cur1;
2.3，實現類似Oracle SYS_CONNECT_BY_PATH的功能，遞歸過程輸出某節點id路徑
-- pro_cre_pathlistUSE csdnDROP PROCEDURE IF EXISTS pro_cre_pathlistCREATE PROCEDURE pro_cre_pathlist(IN nid INT,IN delimit VARCHAR(10),INOUT pathstr VARCHAR(1000))BEGIN DECLARE done INT DEFAULT 0; DECLARE parentid INT DEFAULT 0; DECLARE cur1 CURSOR FOR SELECT t.parent_id,CONCAT(CAST(t.parent_id AS CHAR),delimit,pathstr) FROM channel AS t WHERE t.id = nid; DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = 1; SET max_sp_recursion_depth=12; OPEN cur1; FETCH cur1 INTO parentid,pathstr; WHILE done=0 DO CALL pro_cre_pathlist(parentid,delimit,pathstr); FETCH cur1 INTO parentid,pathstr; END WHILE; CLOSE cur1; DELIMITER ;
2.4，遞歸過程輸出某節點name路徑
-- pro_cre_pnlistUSE csdnDROP PROCEDURE IF EXISTS pro_cre_pnlistCREATE PROCEDURE pro_cre_pnlist(IN nid INT,IN delimit VARCHAR(10),INOUT pathstr VARCHAR(1000))BEGIN DECLARE done INT DEFAULT 0; DECLARE parentid INT DEFAULT 0; DECLARE cur1 CURSOR FOR SELECT t.parent_id,CONCAT(t.cname,delimit,pathstr) FROM channel AS t WHERE t.id = nid; DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = 1; SET max_sp_recursion_depth=12; OPEN cur1; FETCH cur1 INTO parentid,pathstr; WHILE done=0 DO CALL pro_cre_pnlist(parentid,delimit,pathstr); FETCH cur1 INTO parentid,pathstr; END WHILE; CLOSE cur1; DELIMITER ;
2.5，調用函數輸出id路徑
-- fn_tree_pathDELIMITERDROP FUNCTION IF EXISTS csdn.fn_tree_pathCREATE FUNCTION csdn.fn_tree_path(nid INT,delimit VARCHAR(10)) RETURNS VARCHAR(2000) CHARSET utf8 BEGIN DECLARE pathid VARCHAR(1000); SET pathid=CAST(nid AS CHAR); CALL pro_cre_pathlist(nid,delimit,pathid); RETURN pathid; END
2.6，調用函數輸出name路徑
-- fn_tree_pathname-- 調用函數輸出name路徑 DELIMITERDROP FUNCTION IF EXISTS csdn.fn_tree_pathnameCREATE FUNCTION csdn.fn_tree_pathname(nid INT,delimit VARCHAR(10)) RETURNS VARCHAR(2000) CHARSET utf8 BEGIN DECLARE pathid VARCHAR(1000); SET pathid=''; CALL pro_cre_pnlist(nid,delimit,pathid); RETURN pathid; ENDDELIMITER ;
2.7，調用過程輸出子節點
-- pro_show_childLst DELIMITER-- 調用過程輸出子節點 DROP PROCEDURE IF EXISTS pro_show_childLstCREATE PROCEDURE pro_show_childLst(IN rootId INT) BEGIN DROP TEMPORARY TABLE IF EXISTS tmpLst; CREATE TEMPORARY TABLE IF NOT EXISTS tmpLst (sno INT PRIMARY KEY AUTO_INCREMENT,id INT,depth INT); CALL pro_cre_childlist(rootId,0); SELECT channel.id,CONCAT(SPACE(tmpLst.depth*2),'--',channel.cname) NAME,channel.parent_id,tmpLst.depth,fn_tree_path(channel.id,'/') path,fn_tree_pathname(channel.id,'/') pathname FROM tmpLst,channel WHERE tmpLst.id=channel.id ORDER BY tmpLst.sno; END
2.8，調用過程輸出父節點
-- pro_show_parentLstDELIMITER-- 調用過程輸出父節點 DROP PROCEDURE IF EXISTS `pro_show_parentLst`CREATE PROCEDURE `pro_show_parentLst`(IN rootId INT) BEGIN DROP TEMPORARY TABLE IF EXISTS tmpLst; CREATE TEMPORARY TABLE IF NOT EXISTS tmpLst (sno INT PRIMARY KEY AUTO_INCREMENT,id INT,depth INT); CALL pro_cre_parentlist(rootId,0); SELECT channel.id,CONCAT(SPACE(tmpLst.depth*2),'--',channel.cname) NAME,channel.parent_id,tmpLst.depth,fn_tree_path(channel.id,'/') path,fn_tree_pathname(channel.id,'/') pathname FROM tmpLst,channel WHERE tmpLst.id=channel.id ORDER BY tmpLst.sno; END
3，開始測試：
3.1，從根節點開始顯示，顯示子節點集合：
mysql> CALL pro_show_childLst(-1);+----+-----------------------+-----------+-------+-------------+----------------------------+| id | NAME | parent_id | depth | path | pathname |+----+-----------------------+-----------+-------+-------------+----------------------------+| 13 | --首頁 | -1 | 1 | -1/13 | 首頁/ || 16 | --左上幻燈片 | 13 | 2 | -1/13/16 | 首頁/左上幻燈片/ || 14 | --TV580 | -1 | 1 | -1/14 | TV580/ || 17 | --幫忙 | 14 | 2 | -1/14/17 | TV580/幫忙/ || 18 | --欄目簡介 | 17 | 3 | -1/14/17/18 | TV580/幫忙/欄目簡介/ || 15 | --生活580 | -1 | 1 | -1/15 | 生活580/ |+----+-----------------------+-----------+-------+-------------+----------------------------+6 rows in set (0.05 sec)Query OK, 0 rows affected (0.05 sec)
3.2，顯示首頁下面的子節點
CALL pro_show_childLst(13);mysql> CALL pro_show_childLst(13);+----+---------------------+-----------+-------+----------+-------------------------+| id | NAME | parent_id | depth | path | pathname |+----+---------------------+-----------+-------+----------+-------------------------+| 13 | --首頁 | -1 | 0 | -1/13 | 首頁/ || 16 | --左上幻燈片 | 13 | 1 | -1/13/16 | 首頁/左上幻燈片/ |+----+---------------------+-----------+-------+----------+-------------------------+2 rows in set (0.02 sec)Query OK, 0 rows affected (0.02 sec)mysql>
3.3，顯示TV580下面的所有子節點
CALL pro_show_childLst(14);mysql> CALL pro_show_childLst(14);| id | NAME | parent_id | depth | path | pathname || 14 | --TV580 | -1 | 0 | -1/14 | TV580/ || 17 | --幫忙 | 14 | 1 | -1/14/17 | TV580/幫忙/ || 18 | --欄目簡介 | 17 | 2 | -1/14/17/18 | TV580/幫忙/欄目簡介/ |3 rows in set (0.02 sec)Query OK, 0 rows affected (0.02 sec)mysql>
3.4，“幫忙”節點有一個子節點，顯示出來：
CALL pro_show_childLst(17);mysql> CALL pro_show_childLst(17);| id | NAME | parent_id | depth | path | pathname || 17 | --幫忙 | 14 | 0 | -1/14/17 | TV580/幫忙/ || 18 | --欄目簡介 | 17 | 1 | -1/14/17/18 | TV580/幫忙/欄目簡介/ |2 rows in set (0.03 sec)Query OK, 0 rows affected (0.03 sec)mysql>
3.5，“欄目簡介”沒有子節點，所以只顯示最終節點：
mysql> CALL pro_show_childLst(18);+--| id | NAME | parent_id | depth | path | pathname || 18 | --欄目簡介 | 17 | 0 | -1/14/17/18 | TV580/幫忙/欄目簡介/ |1 row in set (0.36 sec)Query OK, 0 rows affected (0.36 sec)mysql>
3.6，顯示根節點的父節點
CALL pro_show_parentLst(-1);mysql> CALL pro_show_parentLst(-1);Empty set (0.01 sec)Query OK, 0 rows affected (0.01 sec)mysql>
3.7，顯示“首頁”的父節點
CALL pro_show_parentLst(13);mysql> CALL pro_show_parentLst(13);| id | NAME | parent_id | depth | path | pathname || 13 | --首頁 | -1 | 0 | -1/13 | 首頁/ |1 row in set (0.02 sec)Query OK, 0 rows affected (0.02 sec)mysql>
3.8，顯示“TV580”的父節點，parent_id為-1
CALL pro_show_parentLst(14);mysql> CALL pro_show_parentLst(14);| id | NAME | parent_id | depth | path | pathname || 14 | --TV580 | -1 | 0 | -1/14 | TV580/ |1 row in set (0.02 sec)Query OK, 0 rows affected (0.02 sec)
3.9，顯示“幫忙”節點的父節點
CALL pro_show_parentLst(17);mysql> CALL pro_show_parentLst(17);| id | NAME | parent_id | depth | path | pathname || 17 | --幫忙 | 14 | 0 | -1/14/17 | TV580/幫忙/ || 14 | --TV580 | -1 | 1 | -1/14 | TV580/ |2 rows in set (0.02 sec)Query OK, 0 rows affected (0.02 sec)mysql>
3.10，顯示最低層節點“欄目簡介”的父節點
CALL pro_show_parentLst(18);mysql> CALL pro_show_parentLst(18);| id | NAME | parent_id | depth | path | pathname || 18 | --欄目簡介 | 17 | 0 | -1/14/17/18 | TV580/幫忙/欄目簡介/ || 17 | --幫忙 | 14 | 1 | -1/14/17 | TV580/幫忙/ || 14 | --TV580 | -1 | 2 | -1/14 | TV580/ |3 rows in set (0.02 sec)Query OK, 0 rows affected (0.02 sec)mysql>
以上所述是小編給大家介紹的在Mysql數據庫里通過存儲過程實現樹形的遍歷，希望對大家有所幫助，如果大家有任何疑問請給我留言，小編會及時回復大家的。在此也非常感謝大家對VeVb武林網網站的支持！
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