在MySQL中,IF语句通常用于存储过程或函数中进行条件判断。你可以在IF语句中使用SELECT查询,但需要注意查询的结果必须能够转换为布尔值,以便进行条件判断。 基础概念 IF语句在MySQL中用于根据条件执行不同的SQL语句块。其基本语法如下: 代码语言:txt 复制 IF search_condition THEN statement_list [ELSEIF search_condi...
IF语句是MYSQL中的一种条件判断语句,用于根据条件的真假来执行不同的操作。在SELECT查询中,可以使用IF语句来实现条件筛选和结果处理。 IF语句的语法如下: 代码语言:txt 复制 IF(condition, value_if_true, value_if_false) 其中,condition是一个条件表达式,value_if_true是当条件为真时返回的值,value_if_false是...
SELECT * FROM employees WHERE salary>12000; 1. 2. #例:查询部门编号不等于90号的员工名和部门编号 SELECT CONCAT(last_name,first_name),department_id FROM employees WHERE department_id<>90; 1. 2. 3. 4. 5. 6. 7. 二、按条件表达式筛选 #例:查询工资在10000到20000之间的员工名、工资以及奖金 ...
NULL);INSERTINTOstudentsVALUES(2,'Bob',45,NULL);INSERTINTOstudentsVALUES(3,'Charlie',60,NULL);-- 更新及格字段UPDATEstudentsSETpass=IF(score>=60,'及格','不及格');-- 查询结果SELECTstudent_id,student_name,score,IF(score
+---+---+---+---+ 查询工资低于 50000的标记为under 查询工资高于 60000的标记为over 其余记为ok selectemp_no, copy salary,casewhensalary<=50000then'underpaid'whensalary>=60000then'overpaid'else'ok'endasstatusfromsalaries
在MySQL中,可以使用SELECT IF语句进行条件判断和选择。SELECT IF语句的语法如下:SELECT IF(condition, value_if_true, value_if_false) FROM table_name;其中,condition是一个条件表达式,value_if_true是当条件为真时要返回的值,value_if_false是当条件为假时要返回的值,table_name是要从中选择数据的表名。以下...
MariaDB [test]>insertintoyourbooksselect*frombooks; Query OK,8rowsaffected (0.002sec) Records:8Duplicates:0Warnings:0 现在books表里的内容就复制到了yourbooks中,可以用select * from yourbooks;命令来验证。 检索(查询)数据 selecttitlefrombooks;# 从books表中检索title(书名)SELECT title FROM books LIMIT...
if exists(SELECT 1 FROM table WHERE id=@id) begin // do something here... end Any help would be greatly appreciated! On another note, I read that there are plans, or at least a feature request, to support something along the lines of T-SQL's @@ERROR, where in you can check if ...
in set (0.00 sec) mysql> select version(); +---+ | version() | +---+ | 4.0.14-standard | +---+ 1 row in set (0.00 sec) As a result, I would expect 'Y' in above query (I mean, it should not make a difference if i substract 24 HOURs from a DATE or 1 DAY) (...
ABOVE QUERY NOT WORKING IN MYSQL 8.0 FOLLOWING ERROR OCCURRED ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '.186.7)) Subject ...