Deleting field if the field is exists in temporary table

Question

I have a temporary table and I need to delete a field in this temporary table if the field already exists.

I was trying using query with non temporary table and it is work, but not for temporary table.

create table #mytemp (
fieldA int null,
fieldB int null
)

IF EXISTS ( SELECT 1
FROM INFORMATION_SCHEMA.COLUMNS
WHERE TABLE_NAME = '#mytemp'
AND COLUMN_NAME = 'fieldA'
AND TABLE_SCHEMA = 'DBO' )
BEGIN ALTER TABLE #mytemp DROP COLUMN fieldA END

Answer 1

You were almost there. You need to check the objects in tempdb not the database you are connected to. Also, temporary tables have suffixes to ensure they have a unique name, so you need a LIKE :

CREATE TABLE #mytemp (fieldA int NULL,
                      fieldB int NULL);

IF EXISTS (SELECT 1
           FROM tempdb.INFORMATION_SCHEMA.COLUMNS
           WHERE TABLE_NAME LIKE N'#mytemp%'
             AND COLUMN_NAME = N'fieldA'
             AND TABLE_SCHEMA = N'dbo' )
BEGIN
    ALTER TABLE #mytemp DROP COLUMN fieldA;
END;