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mysql存儲過程多級目錄樹型

錢多多2年前9瀏覽0評論

MySQL存儲過程可以實現(xiàn)多級目錄樹型結(jié)構(gòu)的存儲和查詢。具體實現(xiàn)方式如下:

DELIMITER $$
CREATE PROCEDURE sp_get_tree(IN parent_id INT)
BEGIN
DECLARE isLeaf INT DEFAULT 0;
DECLARE nodeId INT;
DECLARE nodeName VARCHAR(50);
DECLARE cursor_node CURSOR FOR SELECT id, name, is_leaf FROM tree WHERE parent_id = parent_id;
DECLARE CONTINUE HANDLER FOR NOT FOUND SET @flag = 0;
SET @flag = 1;
OPEN cursor_node;
FETCH cursor_node INTO nodeId, nodeName, isLeaf;
WHILE @flag DO
IF isLeaf THEN
SELECT CONCAT(LPAD("", 2*(parent_id-1), "-"), '-', nodeName) AS tree_name FROM tree WHERE id = nodeId;
ELSE
CALL sp_get_tree(nodeId);
END IF;
FETCH cursor_node INTO nodeId, nodeName, isLeaf;
END WHILE;
CLOSE cursor_node;
END $$
DELIMITER ;

以上代碼中,存儲過程中通過遞歸查詢子節(jié)點實現(xiàn)了多級目錄樹型結(jié)構(gòu)的查詢,并使用LPAD和CONCAT函數(shù)實現(xiàn)了樹狀結(jié)構(gòu)的展示。