Sql 我想更新现有记录我该怎么做？

我有三张桌子：

CREATE TABLE employee(
presismail varchar(50) NOT NULL,
name varchar (50),
lastname varchar (50),
CONSTRAINT presismail PRIMARY KEY (presismail))

CREATE TABLE users(
usermail varchar(50)NOT NULL,
nomail varchar (2),
CONSTRAINT usermail PRIMARY KEY (usermail))


CREATE TABLE assignment(
presismail varchar(50)NOT NULL,
usermail varchar(50)NOT NULL,
senddates varchar (20)NOT NULL,
answervalue varchar (3),
receivedates varchar (20)
CONSTRAINT PK_assignment PRIMARY KEY (presismail, usermail, senddates),
FOREIGN KEY (presismail) REFERENCES employee(presismail),
FOREIGN KEY (usermail) REFERENCES users(usermail))

我想创建一个StoredProcess，将值添加到已选择的两列中

insert into assignment(answervalue, receivedates)
values (@answervalue, @receivedates)
select answervalue, receivedates
from assignment
where presismail = @presismail
and usermail = @usermail
and senddates = @senddates

---

我该怎么做？

我想你想更新一条现有记录

UPDATE assignment
SET    answervalue = @answervalue, 
       receivedates = @receivedates
WHERE  presismail = @presismail
       AND usermail = @usermail
       AND senddates = @senddates

试试这个

insert into assignment(answervalue, receivedates) 
select answervalue, receivedates 
from assignment 
where --------

---

您的问题不清楚，您能给出示例记录吗？您使用的是哪种DBMS？太好了！正是我想要的：）也许我描述得不好：/你可以简单地修改你的问题，并要求你更新现有的记录。