问带有if else的sqlQueryEN我用C#编程语言和visual studio实现了学生信息系统的自动化。我使用MSSQL作为数据库。一开始，我创建了很多不同的表，比如学生、老师、家长、讲座和管理员。但后来我决定把它们收集在一张桌子上。这就是我的问题。或者像@mjwills建议的那样，你可以在没有if条件的情况下完成：private
在SQL中,可以使用以下两种方式将if子句添加到查询中: 使用CASE语句: CASE语句允许在查询中使用条件逻辑。它的语法如下: 使用CASE语句: CASE语句允许在查询中使用条件逻辑。它的语法如下: 在这个语法中,可以根据条件选择不同的结果。每个条件都可以是一个布尔表达式,当条件满足时,将返回相应的结果。ELSE子句是可选的...
//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. ...
# MySQL中的IF-ELSE标签在MySQL中,IF-ELSE标签是一种条件控制语句,用于根据条件执行不同的代码块。它可以帮助我们根据不同的情况进行逻辑判断,并执行相应的操作。在数据库中,IF-ELSE标签通常用于存储过程、函数或触发器中。## IF-ELSE语法IF-ELSE语法如下所示:```sqlIF condition THEN statement1;ELSE MySQL 甘...
像这样：mysql_query("...(irrelevant code).. IF(action==2&&state==0){state=1}");然后在我...
SQL העתק IF 1 = 2 PRINT 'Boolean expression is true.' ELSE PRINT 'Boolean expression is false.'; GO B. Use a query as part of a Boolean expressionThe following example executes a query as part of the Boolean expression. Because there are 10 bikes in the Product table ...
SQL Copy IF 1 = 2 PRINT 'Boolean expression is true.' ELSE PRINT 'Boolean expression is false.'; GO B. Use a query as part of a Boolean expression The following example executes a query as part of the Boolean expression. Because there are 10 bikes in the Product table that meet ...
SQL Kopiuj IF 1 = 2 PRINT 'Boolean expression is true.' ELSE PRINT 'Boolean expression is false.'; GO B. Use a query as part of a Boolean expression The following example executes a query as part of the Boolean expression. Because there are 10 bikes in the Product table that meet...
SQL IF 1 = 2 PRINT 'Boolean expression is true.' ELSE PRINT 'Boolean expression is false.'; GO B. Use a query as part of a Boolean expression The following example executes a query as part of the Boolean expression. Because there are 10 bikes in theProducttable that meet the condition...
SQL Copy IF 1 = 2 PRINT 'Boolean expression is true.' ELSE PRINT 'Boolean expression is false.'; GO B. Use a query as part of a Boolean expression The following example executes a query as part of the Boolean expression. Because there are 10 bikes in the Product table that meet ...