Update statement is giving an invalid column name error, even though the column exists I have a temporary table created at the beginning of this stored procedure. It is created successfully and can be selected from and inserted to. Here is the create statement

CREATE TABLE #tmpImportData 
( GuideFirstName VARCHAR(MAX), 
  GuideLastName VARCHAR(MAX), 
  email VARCHAR(MAX), 
  group_id_text VARCHAR(MAX), 
  CandidateName VARCHAR(MAX), 
  grade_text VARCHAR(5), 
  dateofbirth DATE
)


My problem is trying to update a column after I alter the temporary table. I get the error:


  Msg 207, Level 16, State 1
  invalid column name


Code:

declare @SQl1 nvarchar(max)
set @SQL1 ='
ALTER TABLE #tmpImportData 
ADD group_id INT
ALTER TABLE #tmpImportData 
ADD guide_id INT
ALTER TABLE #tmpImportData 
ADD password_plain_text VARCHAR(500)
ALTER TABLE #tmpImportData 
ADD guide_email VARCHAR(500)
ALTER TABLE #tmpImportData 
ADD class_id INT'

exec sp_executesql @Sql1

UPDATE #tmpImportData 
SET group_id = CAST(group_id_text AS INT)

UPDATE #tmpImportData 
SET group_id = 0 WHERE group_id IS NULL


Solution: NOT THE SOLUTION ANYMORE, IT DOESN'T WORK ANYMORE

declare @SQl1 nvarchar(max)
set @SQL1 ='
ALTER TABLE #tmpImportData ADD group_id INT
ALTER TABLE #tmpImportData ADD guide_id INT
ALTER TABLE #tmpImportData ADD password_plain_text VARCHAR(500)
ALTER TABLE #tmpImportData ADD guide_email VARCHAR(500)
ALTER TABLE #tmpImportData ADD class_id INT'

exec sp_executesql @Sql1
WAITFOR DELAY '000:00:05'

UPDATE #tmpImportData SET group_id = CAST(group_id_text AS INT)
UPDATE #tmpImportData SET group_id = 0 WHERE group_id IS NULL


What I thought would be better but still throws the invalid column name error Msg 207, Level 16, State 1, Line 2
Invalid column name 'group_id'.:

  declare @SQl1 nvarchar(max)
set @SQL1 ='
ALTER TABLE #tmpImportData ADD group_id INT, guide_id INT, password_plain_text VARCHAR(500), guide_email VARCHAR(500), class_id INT; UPDATE #tmpImportData SET group_id = CAST(group_id_text AS INT);
UPDATE #tmpImportData SET group_id = 0 WHERE group_id IS NULL; '

exec sp_executesql @Sql1
WAITFOR DELAY '000:00:05'

--UPDATE #tmpImportData SET group_id = CAST(group_id_text AS INT)
--UPDATE #tmpImportData SET group_id = 0 WHERE group_id IS NULL

SELECT * FROM #tmpImportData
You need to perform the update in dynamic SQL too (or just create the table with all columns in the first place). The error is happening because the update with the new column is being parsed before the dynamic SQL has run.

As an aside, you are probably only getting this error if you try to execute the stored procedure and choose 'Display estimated execution plan' in the toolbar. This is a parsing/binding error that will happen in many scenarios when generating an estimated plan involving #temp tables, but shouldn't happen during normal execution. 

So to avoid the error during retrieval of an estimated plan, put any "new" column references in separate dynamic SQL blocks. But to really avoid the problem: stop retrieving estimated execution plans. They're pretty worthless anyway.