Re: Recursive Procedure or Function in Mysql 13075 Roland Bouman February 10, 2007 03:42AM Re: Recursive Procedure or Function in Mysql 4827 MuraliDharan V February 11, 2007 11:00PM Re: Recursive Procedure or Function in Mysql 4613
with recursive xx(xx1,xx2,xx3) as () select xx1,xx2,xx3 from xx 这个语法就是创建一个临时递归视图(CTE 语法),mysql内置的递归查询语法,不同于后端写递归查询,我们不需要多次请求数据库,我们只需要根据查询结果进行组装即可,因此可以减轻mysql服务器负载,不过既然是递归,当数据量很大时,这样写压力依旧会很...
CREATEFUNCTION`f_GetDepartmentName` (didint)RETURNSvarchar(100) READS SQL DATA DETERMINISTIC BEGIN declarestrvarchar(100); return(selectdeptNamefromdudeptwhereId=did); END$$ DELIMITER ; selectf_GetDepartmentName(1); -- MySQL 自定义函数,实现递归查询 delimiter $$ dropfunctionif exists `getChildLis...
SQL: Recursive query in MySQL,DROP TABLE IF EXISTS `dudept`;CREATE TABLE `dudept` ( `Id` int(11) NOT NULL AUTO_INCREMENT comment 'ID', `deptCode` varchar(10) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL comment'', `deptName
Ok, go to the business now. If you want to use recursive in mysql,you need to do the three step first: 1. Open your mysql config file from the mysql installation location. 2. Set the recursive depth to the max value: max_sp_recursion_depth=255 ...
In MySQL, we use recursive common table expressions (CTEs) to write recursive queries:WITH RECURSIVE cte SELECT columns FROM ... We define a recursive CTE using the WITH RECURSIVE construct. It contains a recursive and nonrecursive SELECT statement:WITH RECURSIVE cte(columns) AS ( nonrecursive ...
It was written at the times of MySQL 4.1 but it still holds.In his blog Mike has two points:arbitrarily-deep hierarchies are difficult to handle with traditional SQL: either a stored procedure must be written (with WHILE loops and recursive procedure calls, to find an ite...
Derived tables exist in MySQL since long. It’s accurate to say that non-recursive CTEs are “improved derived tables”. Here is a first example: WITH cte1(txt) AS (SELECT "This "), cte2(txt) AS (SELECT CONCAT(cte1.txt,"is a ") FROM cte1), cte3(txt) AS (SELECT "nice que...
Description: I have read in a pretty decent book (about MySQL) about recurrent functions. Pretty obvious for me, so it was a bit of surprise that I am using much newer version of the MySQL than the author of the book and I cannot use recursion. How to repeat: Just run any function ...
Now, we have a left and a right number for each node in the tree, that is, the left number is the one we took when we first descended to the node, the right number is the number we took when we encountered the node for the second time when we ascended back again: A (1..10...