How can I update table column values from YYYYMMDD to YYYYMM

So I want to convert the dates to be

SELECT CAST(convert(varchar(6),a.Account_Open_Date,112) as int) FROM [tempdb].[dbo].[SQL Test Data] a WHERE Account_Open_Date is NOT NULL;

This select statement pulls up the dates how I want them but I want to update the table to the same format and am having a hard time with Updating. I don’t have a good example of what I have tried.

update x.Account_Open_Date SET a.Account_Open_Date = CAST(convert(varchar(6),Account_Open_Date,112) as int) FROM ( [tempdb].[dbo].[SQL Test Data] ) x WHERE Account_Open_Date is NOT NULL;

>Solution :

The comments bring up excellent points. Seeing as you are doing this on a temp table I will assume you are testing and wont dive into the points brought up.

Fixed your update statement. You were close.

update x 
SET 
    x.Account_Open_Date = CAST(convert(varchar(6),Account_Open_Date,112) as int) 
FROM 
    [tempdb].[dbo].[SQL Test Data] x 
WHERE 
   Account_Open_Date is NOT NULL;