Drop all the -obe columns in a DB

  • The problem is that I have a lot of "–obe" i.e. something company-obe in compay table validUsers-obe in validUser table and some other -obe colimns in various other table ( approx about 57 columns in various table ), these obsolete columns are obviously never used and are somewhat impeding the performance.

    So I would like to know if there is a way that we can select all the –obe columns and delete all the –obe columns rather than having to delte them indivisually with the drop statement .

    Now I know how to list them all but I have not been able to comeup with a solution that will drop all the –obe columns.

    Could you please guide me as to how this can be accomplished.

    Thanks

  • well, you could use something like this:

    SELECT 'ALTER TABLE ' +

    t.Table_Name +

    ' drop column ' +

    c.Column_Name +

    ';'

    FROM Information_Schema.tables t

    INNER JOIN Information_Schema.columns C

    ON t.Table_name = c.Table_name

    WHERE c.Column_Name LIKE '%-obe'

    Even though this is completely untested, and I would not recommend dropping columns in a bulk operation, but whatever your needs are, this might work.

    Cheers,

    J-F

  • You can't do it in one statement. You could write a script that creates a script for you like:

    DECLARE @sql NVARCHAR(4000)

    SELECT

    @sql = COALESCE(@sql, N'') + N'Alter Table ' + S.[name] + N'.' + T.[name] + ' Drop Column ' + AC.NAME + NCHAR(10)

    FROM

    sys.all_columns AS AC JOIN

    sys.tables AS T ON AC.[object_id] = T.[object_id] JOIN

    sys.schemas AS S ON T.[schema_id] = S.[schema_id]

    WHERE

    AC.[name] LIKE '%-obe'

    SELECT @sql

    Always test first and make sure you have a good backup before dropping any columns in production.

  • Thanks that works,thanK you so much

    thers is somehting else i am struggling with While upsizing from access to SQL all the IsActive fields that are of bit type are upsized with null not allowed and we need them to allow null is there a script that would do this and also the memo fields on access are trasnferred as ntext can we change them all with a script to nvarchar(MAX),i.e all the columns IsActive Columns are set to Allow null and all the ntext fields are set as nvarchar(max)

    As of now i have been doing the alter one at a time

    thanks again

  • Just have same problem

    thanks too

    use

    while EXISTS (SELECT * FROM sys.columns where [name] LIKE '%-obe')

    begin

    DECLARE @sql NVARCHAR(4000)

    SELECT

    @sql = N'Alter Table ' + T.[name] + N' Drop Column ' + C.NAME

    FROM

    sys.columns AS C JOIN

    sys.tables AS T ON C.[object_id] = T.[object_id]

    WHERE

    C.[name] LIKE '%-obe';

    exec sp_executesql @sql;

    end

    It droops all columns in DB

  • avi-631555 (9/24/2009)


    Thanks that works,thanK you so much

    thers is somehting else i am struggling with While upsizing from access to SQL all the IsActive fields that are of bit type are upsized with null not allowed and we need them to allow null is there a script that would do this and also the memo fields on access are trasnferred as ntext can we change them all with a script to nvarchar(MAX),i.e all the columns IsActive Columns are set to Allow null and all the ntext fields are set as nvarchar(max)

    As of now i have been doing the alter one at a time

    thanks again

    I dont know why you want to make a bit column nullable, but here is a script similar to the one posted in the earlier post.

    DECLARE @sql NVARCHAR(4000)

    SELECT

    @sql = COALESCE(@sql, N'') + N'Alter Table ' + T.[TABLE_NAME]+ ' ALTER Column '

    + T.COLUMN_NAME + ' ' + T.DATA_TYPE + ' NULL ' +

    NCHAR(10)

    FROM

    information_schema.columns T

    WHERE

    T.[COLUMN_NAME] LIKE 'IsActive%' -- Put the correct where condition here

    SELECT @sql

    "Keep Trying"

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