1是常量，在这里只是代表存在 如果inserted或deleted表中无数据，那么select不会出数据 如果表中有数据，select会显示1 这里写1与*作用相同，exists只判断是否有数据，不会将数据输出
创建触发器的示例代码 CREATETRIGGERtrg_CheckSalaryONEmployeesAFTERINSERT,UPDATEASBEGINIFEXISTS(SELECT*FROMinsertedWHERESalary<3000)BEGINRAISERROR('Salary must be at least 3000.',16,1);ROLLBACKTRANSACTION;ENDEND 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 代码逻辑分析 触发器声明:触发器trg_CheckS...
下面是设置if条件的代码: IFEXISTS(SELECT*FROMinsertedWHEREAge<18)BEGINUPDATEUsersSETName='未成年'WHEREIDIN(SELECTIDFROMinsertedWHEREAge<18);END 1. 2. 3. 4. 5. 6. 执行相应操作:最后,在if条件中,我们可以执行相应的操作。在上面的例子中,如果插入的数据年龄小于18岁,则将名字设为“未成年”。如果不...
ELSE IF EXISTS (SELECT * FROM deleted) BEGIN PRINT 'Rows updated' -- Update data in another table UPDATE [dbo].[additional_table] SET column1 = inserted.column3 FROM [dbo].[additional_table] INNER JOIN inserted ON inserted.id = [dbo].[additional_table].id END -- Check if DELETE ELSE...
to be updated if it already exists and inserted if it does not. If we refer to the Books Online documentation, it gives examples that are similar to: IF EXISTS (SELECT * FROM Table1 WHERE Column1='SomeValue') UPDATE Table1 SET (...) WHERE Column1='SomeValue' ELSE INSERT INTO Table...
to be updated if it already exists and inserted if it does not. If we refer to the Books Online documentation, it gives examples that are similar to: IF EXISTS (SELECT * FROM Table1 WHERE Column1='SomeValue') UPDATE Table1 SET (...) WHERE Column1='SomeValue' ELSE INSERT INTO Table...
Notice that even though we only altered one row, the result indicates that two rows were affected because we actually DELETED the existing row then INSERTED the new row to replace it. More information on using REPLACE can be found in the official documentation. Зарамками Agile The...
我也搜索了很多文档和 SO 帖子,但我找不到一种语法,它在一个查询中对两种数据库类型都执行此操作。 SQL Server 查询: IF (EXISTS (SELECT * FROM failed_logins_ip_address WHERE ip_address = 'xxx')) BEGIN UPDATE failed_logins_ip_address
以下是一个示例触发器,其中包含 IF ELSE 语句: CREATE TRIGGER [dbo].[trig_example] ON [dbo].[example_table] AFTER INSERT, UPDATE, DELETE AS BEGIN -- Check if INSERT IF EXISTS (SELECT * FROM inserted) BEGIN PRINT 'New rows added' -- Insert additional data into another table INSERT INTO ...
SELECT EmployeeID, Name, Surname, Age, DATEADD(SECOND, 1, @now) FROM inserted; END GO In case there is a need to update due to some employees celebrating their birthday, UPDATE dbo.EmployeeHistoryStuff SET Age += 1 WHERE EmployeeID IN (1,2); ...