SQL存储过程IF ELSE逻辑错误

Question

I am trying to implement an insert stored procedure. Basically, how it works is the stored procedure will check whether the record exists or not, then proceed to perform insert. A variable @status will be used as indicator. However, I found out a particular problem with this query is that when I execute the query , it will return the result @status = 1 no matter the data existed or not. However, the INSERT function is fine without any problems just the @status . The following is my implementation:

CREATE PROCEDURE save_proc
(
  @userid varchar(10)
  @name varchar(30)
)

AS

DECLARE @status int

  if exists ( SELECT * FROM table1 where userID = @userid AND userName = @name)
    SET @status = 0

  else
    INSERT INTO table1 (userID, userName) VALUES (@userid, @name)
    SET @status = 1

SELECT @status

Answer 1

else
begin
    INSERT INTO table1 (userID, userName) VALUES (@userid, @name)
    SET @status = 1
end

Modify code as above. You haven't defined scope of your else. It was upto insert statement only. SET @status = 1 was executed everytime

Answer 2

Try to put it in BEGIN END

CREATE PROCEDURE save_proc
(
  @userid varchar(10)
  @name varchar(30)
)

AS

DECLARE @status int

  if exists ( SELECT * FROM table1 where userID = @userid AND userName = @name)
    SET @status = 0

    else
    begin
        INSERT INTO table1 (userID, userName) VALUES (@userid, @name)
        SET @status = 1
    end

If you are not putting the BEGIN END then the scope of your else statement is just the next line which is getting executed ie, INSERT INTO table1 (userID, userName) VALUES (@userid, @name) is only under the scope of else block. And SET @status = 1 is outside the scope of else block. So once the else block executes the next query will be executed which is SET @status = 1

On a side note:

When you are checking for if exists then don't use the * wildcard. Instead you can use 1 ie,

if exists ( SELECT 1 FROM table1 where userID = @userid AND userName = @name)