Each statement_list consists of one or more SQL statements; an empty statement_list is not permitted. An IF ... END IF block, like all other flow-control blocks used within stored programs, must be terminated with a semicolon, as shown in this example: ...
Each statement_list consists of one or more SQL statements; an empty statement_list is not permitted. An IF ... END IF block, like all other flow-control blocks used within stored programs, must be terminated with a semicolon, as shown in this example: ...
在MySQL中,IF语句通常用于在查询中根据条件返回不同的值。它可以在SELECT语句、存储过程或函数中使用。以下是IF语句的基本语法: 在SELECT语句中使用IF 代码语言:txt 复制 SELECT column1, column2, IF(condition, value_if_true, value_if_false) AS result_column FROM table_name;...
//mapper中需要传递一个容器 public List<User> queryByIdList(List<Integer> userIdList); SELECT * FROM user WHERE userId IN <foreach collection="userIdList" item="id" index="index" open="(" close=")" separator=","> #{id} </foreach> 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. ...
Summary: in this tutorial, you will learn how to use MySQL IF statement to execute a block of SQL code based on conditions. The MySQL IF statement allows you to execute a set of SQL statements based on a certain condition or value of an expression. To form an expression in MySQL, you...
Use CASE for multiple conditions.Consider using the `CASE` statement for evaluating multiple conditions, as it is more readable and flexible compared to `IF`. Watch for nulls.Ensure that the condition handles `NULL` values appropriately, as they can affect the logic. ...
You can use the IF function directly in theSELECT statementwithout theFROMand other clauses as follows: SELECT IF(1 = 2,'true','false'); -- false SELECT IF(1 = 1,' true','false'); -- true Displaying N/A instead of NULL using MySQL IF function ...
UsingINSERT IGNOREeffectively causes MySQL to ignore execution errors while attempting to performINSERTstatements. This means that anINSERT IGNOREstatement which contains a duplicate value in aUNIQUEindex orPRIMARY KEYfielddoes notproduce an error, but will instead simply ignore that particularINSERTcommand...
I'm pretty new to MySQL and I have a problem here with an IF statement inside a stored procedure. Here's the stored procedure, as you can see nothing too fancy, it includes 3 actions... : -- Create order_products stored procedure ...
MySql 游标的使用 今天在极客时间学习了SQL必知必会专栏,游标的部分,在下面总结一下游标的使用。...使用游标的步骤如下:定义游标,用变量接收游标状态,打开游标,游标中取得数据,关闭游标,释放游标,下面就从这是步骤来使用游标。...定义游标 DECLARE cursor_name CURSOR FOR select_statement cursor_name 为游标名称,...