Question

Is there a way to apply an alter statement to ALL the columns in a table without having to specify the column names? This would only be used in a temp table I need to clean up the duplicate data in a report.

Here’s a sample of what I’m wondering if its possible:

select T1.Column1, T1.Column2, T1.Column3, T2.Column1, T2.Column2
into #templateTable
from Table1 T1
join Table2 T2 on T1.Column1 = T2.Column2

alter table #templateTable
alter column * null

All I really need is my #tempTable to allow null values in the columns that it originally gets data from which don’t previously allow null values.

Lastly, there are 2 reasons I don’t want to go through and edit each column:

1. There are many columns (~50) being pulled from at least 10 tables.
2. I don’t know which ones allow null and researching which ones do would take me the next two days.

Any help will be appreciated.

Answer 1

Ugly way, but it works in a SqlServer Management Studio, at least (can probably be used as “strings”)

select 'alter table ' + table_name + ' alter column '+ column_name +' ' + data_type + 
(case 
  when character_maximum_length is not null and CHARACTER_MAXIMUM_LENGTH <> -1 then ' (' + CAST(CHARACTER_MAXIMUM_LENGTH as varchar) +')' 
  when CHARACTER_MAXIMUM_LENGTH = -1 then '(MAX)'
  else '' end)  + ' null;'  from tempdb.information_schema.COLUMNS
where TABLE_NAME = '<YOUR TABLE NAME>'
and IS_NULLABLE='NO';

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