drop function if exists [函数名]; delimiter [结束标记] create function [函数名]([参数1], [参数2] ...) returns [返回值类型] begin [方法体] return [返回值]; end [结束标记] delimiter ; 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 参数,其格式为param_name type,如username varchar(20)。
mysql函数的if else mysql函数的序列错误 一、执行创建函数提示如下错误 错误:ERROR 1418 (HY000): This function has none of DETERMINISTIC, NO SQL, or READS SQ L DATA in its declaration and binary logging is enabled (you *might* want to use the less safe log_bin_trust_function_creators variable...
首先,在MySQL中创建一个存储过程: 代码语言:txt 复制 DELIMITER // CREATE PROCEDURE CheckCondition(IN input INT) BEGIN IF input > 0 THEN SELECT 'Positive'; ELSE SELECT 'Non-positive'; END IF; END // DELIMITER ; 然后,在C#中调用这个存储过程: ...
I have stored the next invoice number in a file called Storage01 in the field Nextra5. The code below deals with this and is accepted by MySQL Workbench but when I try to run it I get an error "Not allowed to return a result set from a function". But if I remove the Function, ...
以下是一个简单的MySQL存储过程示例,展示了如何使用IF-ELSE语句: 代码语言:txt 复制 DELIMITER // CREATE PROCEDURE GetEmployeeStatus(IN employee_id INT) BEGIN DECLARE status VARCHAR(20); SELECT status INTO status FROM employees WHERE id = employee_id; IF status = 'active' THEN SELECT 'Employee is...
MySQLIFfunction is one of the MySQL control flow functions that returns a value based on a condition. TheIFfunction is sometimes referred to asIF ELSEorIF THEN ELSEfunction. The syntax of the MySQLIFfunction is as follows: 1IF(expr,if_true_expr,if_false_expr) ...
MySQLIFfunction is one of the MySQL control flow functions that returns a value based on a condition. TheIFfunction is sometimes referred asIF ELSEorIF THEN ELSEfunction. The syntax of the MySQL IF function is as follows: IF(expr,if_true_expr,if_false_expr) ...
if if(value,value2,value3),如果value结果为true(一般为表达式),返回value2,否则value3 case when 方式1(相当Java的if..else if.. else) case when 条件1 then 结果1 when 条件2 then 结果2
我们日常开发的项目中,如果代码中存在大量的if-else语句,阅读起来非常的折磨(直接劝退),维护起来也很难,也特别容易出问题。比如说以下: 接下来,本文介绍我们常使用的8种方法去优化if-else。 1、提前return,让正常流程走主干 如果if-else代码中包含return语句,或者我们可以将包含if-else的代码从主干中抽取到一个单独...
插入/删除自己这个表 -- 导致 MySQL 发生异常 DELETE FROM OrderDetail WHERE ID = new.GoodsID; ELSE UPDATE Goods SET Amount = Amount - new.Amount WHERE ID = new.GoodsID; END IF;END;//DELIMITER ;处理前mysql> select * from goods;+---+--...