Question

我试图检查记录是否存在，然后再进行更新

这是我目前所拥有的:(显然不起作用）

    CREATE PROCEDURE dbo.update_customer_m
       @customer_id             INT                      , 
       @firstname               VARCHAR(30)          , 
       @surname                 VARCHAR(30)              , 
       @gender                  VARCHAR(6)               , 
       @age                     INT                  , 
       @address_1               VARCHAR(50)      , 
       @address_2               VARCHAR(50)              ,
       @city            VARCHAR(50)              ,
       @phone           VARCHAR(10)              ,
       @mobile          VARCHAR(11)              ,
       @email           VARCHAR(30)              ,               
AS 
    IF EXISTS 
    (
       SELECT *
       FROM dbo.Customer
       WHERE CustID = @customer_id
    )
BEGIN 
       UPDATE dbo.Customer
           SET Firstname = @firstname,  Surname = @surname, Age = @age, Gender = @gender, Address1 = @address_1, Address2 = @address_2, City = @city, Phone = @phone, Mobile = @mobile, Email = @email
       WHERE CustID = @customer_id
END

有更好的方法吗？

Answer 1

为什么要先检查？如果该行不存在，则更新将不更新任何行：

   UPDATE dbo.Customer
       SET Firstname = @firstname,  Surname = @surname, Age = @age, Gender = @gender,
           Address1 = @address_1, Address2 = @address_2, City = @city,
           Phone = @phone, Mobile = @mobile, Email = @email
       WHERE CustID = @customer_id;

不需要if。

Answer 2

如果不需要块，首先选择if是否没有行，Update块什么都不做，没有行受影响。

只需在此过程中编写更新。

但也许你想写其他如果这个程序，如果没关系，你可以IF和ELSE。在IF块中，您可以编写此更新，在ELSE块中，您可以执行另一个需要的操作。

Answer 3

SELECT *
   FROM dbo.Customer
   WHERE CustID = @customer_id
//add this
IF @@ROWCOUNT>=1
BEGIN 
   UPDATE dbo.Customer
       SET Firstname = @firstname,  Surname = @surname, Age = @age, Gender = @gender, Address1 = @address_1, Address2 = @address_2, City = @city, Phone = @phone, Mobile = @mobile, Email = @email
   WHERE CustID = @customer_id
END

如果记录存在则存储过程然后更新

3 个答案: