Getting Duplicates With Select Distinct (full Outer Join)

I am writing a script to create a audit trigger on any table. I am getting duplicate rows inserted into my audit table, only for the primary key columns. Anybody see why?

Right now I am debugging an Insert, so I think you can ignore the "U" update part of the Where clause.



....starts with other code to determine columns and primary key fields for selected table....

--get number of columns
select
@rowId = min(RowId),
@MaxRowId = max(RowId)
from #tblFieldNames

-- Loop through fields and build Sql string
while @RowId <= @MaxRowId
BEGIN
SELECT @fieldname = colName FROM #tblFieldNames WHERE RowId = @RowId

SELECT @sql = 'insert tblAuditAdmin (TableAltered, [Action], FieldName, OldValue, NewValue, UpdateDate, UpdateNumber, UserName)'
SELECT @sql = @sql + ' select distinct''' + @TableName + ''''
SELECT @sql = @sql + ',''' + @TriggerType + ''''
SELECT @sql = @sql + ',''' + @fieldname + ''''
SELECT @sql = @sql + ',convert(varchar(1000),d.' + @fieldname + ')'
SELECT @sql = @sql + ',convert(varchar(1000),i.' + @fieldname + ')'
SELECT @sql = @sql + ',''' + @UpdateDate + ''''
SELECT @sql = @sql + ', 1'
SELECT @sql = @sql + ',''' + @UserName + ''''
SELECT @sql = @sql + ' FROM #ins i FULL OUTER JOIN #del d'
SELECT @sql = @sql + @pkJoinClause
SELECT @sql = @sql + ' WHERE (''' + @TriggerType + ''' = ''I'')'
SELECT @sql = @sql + ' OR (''' + @TriggerType + ''' = ''D'')'
SELECT @sql = @sql + ' OR (''' + @TriggerType + ''' = ''U'' AND '
SELECT @sql = @sql + '((i.' + @fieldname + ' <> d.' + @fieldname + ')'
SELECT @sql = @sql + ' OR (''' + @fieldname + ''' in (Select colName from #primaryKeyFields))'
SELECT @sql = @sql + ' OR (i.' + @fieldname + ' IS NULL AND d.' + @fieldname + ' is NOT null)'
SELECT @sql = @sql + ' OR (i.' + @fieldname + ' IS NOT NULL AND d.' + @fieldname + ' is null)))'

EXEC (@sql)

set @RowId = @RowId + 1
END